Introduction

Local Vibration May Increase Strength of Deconditioned Muscles

Local Vibration Enhances Training

Effect of Local Vibration when Applied During Contraction

Local Vibration During Strength Training

Comparing Foam Rollers to Vibrating Foam Rollers

What is being stimulated

How is it being stimulated

Effect on Reflexes

CNS Involvement

Consideration of Additional Receptors

Muscle Soreness

Pre-exercise Vibration and Chemical Markers of DOMS

Local Vibration for Acute Muscle Pain

The Effects of Local Vibration: Introduction to Vibration Release Techniques

NASM

ACSM

AFAA

NCBTMB

CanFitPro

PTAGlobal

ISSA

REPS

REPSI

PACE

WITS

CIMSPA

AUSPHYSIO

TPTA

NYPT

AOTA

Effects of Local Vibration

The Effects of Local Vibration

Local vibration, that is vibration directly applied to a <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>, was used in studies as early as the 1960s to investigate sensory afferents, reflexes, and motor response (1-6, 9, 12-13, 22, 40-41). Note, this paper has purposefully excluded whole-body and indirect vibration research. Hundreds of studies have been published investigating whole-body vibration training; however, the intent of such training, effects, and mechanisms involved may be different than local vibration.
<h3>Key Points for Practical Application</h3>
<ul>
 <li>Pre-exercise local vibration reduces signs and chemical markers of delayed onset <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> soreness (DOMS) and may improve performance in subsequent frequent workouts.</li>
 <li>Local vibration is effective for reducing acute <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> pain (and can be added to a home program via the devices like the Hypervolt by Hyperice&#xAE; or similar devices).</li>
 <li>Local vibration alone may be sufficient to increase strength in deconditioned muscles/individuals.</li>
 <li>Current research implies that adding vibration to self-administered <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques (SMR) (e.g. foam rolling) enhances benefits for DOMS, pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>, and increasing proprioception. Further research is needed to refine protocols and determine whether adding vibration to SMR enhances benefits for increasing range of motion and improving <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> performance when used as a warm-up.</li>
</ul>
<h4>Summary of Receptor Response to Local Vibration</h4>
<ul>
 <li>Local vibration has been used to study sensory afferents and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> response since the 1960s.</li>
 <li>Studies have demonstrated that high-frequency vibration preferentially stimulates type Ia sensory afferents (dynamic <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindle), and results in much less stimulation of type Ib sensory afferents (Golgi tendon organ) and type II afferents (static <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindle afferents).</li>
 <li>Research suggests that length, stretch, and increased <a id="tension" data-tip="1229" target="_blank" href="/glossary-term/tension" class="glossary">tension</a> in the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> being vibrated increase the facilitation of receptors, including type Ib and type II afferents.</li>
 <li>Local vibration results in simultaneous agonist inhibition and tonic contraction (known as the tonic vibration reflex or TVR), and <a id="reciprocal-inhibition" data-tip="1655" target="_blank" href="/glossary-term/reciprocal-inhibition" class="glossary">reciprocal inhibition</a> of the functional <a id="antagonists" data-tip="1705" target="_blank" href="/glossary-term/antagonists" class="glossary">antagonist</a>.</li>
 <li>Local vibration may result in a reduction in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> <a id="tone" data-tip="1639" target="_blank" href="/glossary-term/tone" class="glossary">tone</a> (H-reflex <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>) while potentiating the reactive component of stretch reflex (T-reflex) associated with the performance of sport and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> activities such as running and jumping.</li>
 <li>Studies demonstrate that the CNS is involved in agonist tonic contraction, inhibition of antagonists, and kinesthesia resulting from local vibration.</li>
 <li>Studies imply that additional mechanoreceptors (Pacinian corpuscles, Ruffini endings, free <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a> endings) play a significant role in motor control and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activity and that Pacinian corpuscles are the receptor most likely to respond to local vibration.</li>
</ul>
<h4>Local Vibration and Pain</h4>
<ul>
 <li>Pre-exercise local vibration may be protective, reducing swelling, improving range of motion, and decreasing pain associated with DOMS.</li>
 <li>Pre-exercise vibration attenuates chemical markers associated with DOMS including decreased CK, LDH, IL6, histamine, lymphocytes, and increased neutrophils.</li>
 <li>Direct application of vibration may have benefits for addressing acute <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> pain (and can be added to a home program via the Hypervolt or similar devices).</li>
</ul>
<h4>Local Vibration and Muscle Performance</h4>
<ul>
 <li>Local vibration alone may be sufficient to increase strength in deconditioned muscles/individuals.</li>
 <li>Pre-exercise local vibration improved <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> performance when exercise was performed on subsequent days (frequently).</li>
 <li>The application of pre-exercise local vibration should be limited to less than 10 minutes per <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>. (The Brookbush Institute protocols suggest 1 - 2 minutes per <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> and no more than 5 minutes)</li>
 <li>The application of local vibration during training may attenuate sub-maximal concentric strength and maximal power; however, the limited benefit, lack of residual effect, and practical issues with wearing vibration technology warrant further study before use in strength and performance settings can be recommended. (Reminder, this is a statement based on studies investigating the direct application of vibration to muscles being trained, and does not include whole-body vibration research)</li>
 <li>Currently, research implies that vibration added to foam rolling has a significant effect on DOMS, pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>, and proprioception, and further research is needed to determine the effect on range of motion and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> performance when used as a warm-up.</li>
 <li>The Brookbush Institute recommends that local vibration (vibration <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques) is used prior to lengthening techniques; however, some studies suggest that there may be some benefit to incorporating local vibration while stretching.</li>
</ul>
<h2><a href="https://www.datocms-assets.com/25800/1649107509-vibration-gastrocnemius.jpeg"><img src="https://www.datocms-assets.com/25800/1649107509-vibration-gastrocnemius.jpeg"></a></h2>

Webinar: Effects of Local Vibration.

Receptor Response

Research has demonstrated that the application of local vibration preferentially stimulates type Ia receptors (dynamic <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindles), with minimal stimulation of type II receptors (static <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindles) and type Ib receptors (Golgi tendon organ) (2-8, 10). Research suggests that increased length, stretch, and <a id="tension" data-tip="1229" target="_blank" href="/glossary-term/tension" class="glossary">tension</a> in the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> being vibrated may increase the facilitation of receptors, including type Ib and type II afferents; however, the increase in facilitation may be the result of an increase in <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a> and not the actual stimulation of action potentials (11, 13-15, 18, 24). These studies imply that local vibration preferentially stimulates sensory afferents associated with dynamic <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindle receptors; the receptors affiliated with stretch reflex. Further, vibration may have little to no effect on the sensory afferents associated with rating <a id="tension" data-tip="1229" target="_blank" href="/glossary-term/tension" class="glossary">tension</a> (type Ib) or static joint position (type II).
<h4>Receptors</h4>
<table>
 <tbody>
 <tr>
 <td>Afferent Nerve Type</td>
 <td>Associated Receptor</td>
 <td>Response</td>
 </tr>
 <tr>
 <td>Type Ia</td>
 <td>Dynamic Muscle Spindle</td>
 <td>Responds to the amount and rate of length change.</td>
 </tr>
 <tr>
 <td>Type Ib</td>
 <td>Golgi Tendon Organ</td>
 <td>Responds to the amount and rate of tension developed.</td>
 </tr>
 <tr>
 <td>Type II</td>
 <td>Static Muscle Spindle</td>
 <td>Provides information about the joint position, even at rest.</td>
 </tr>
 </tbody>
</table>
Interesting Note: A study by Ushiyama et al. demonstrated that vibration elicited a larger response from the <a href="https://brookbushinstitute.com/article/gastrocnemius-plantaris" target="_blank" rel="noopener">gastrocnemius</a> composed of mostly type II <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> fibers, when compared to the <a href="https://brookbushinstitute.com/article/soleus" target="_blank" rel="noopener">soleus</a> composed of mostly type I <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> fibers, providing further evidence that the largest type Ia afferents are preferentially stimulated by vibration (15).

Additional studies have demonstrated that both monosynaptic and polysynaptic type Ia pathways are stimulated with vibration of sufficient frequency and amplitude (6- 8). The expected response of this stimulation would be a stretch reflex mediated increase in activity of the agonist, as well as presynaptic inhibition of the <a id="antagonists" data-tip="1705" target="_blank" href="/glossary-term/antagonists" class="glossary">antagonist</a> (<a id="reciprocal-inhibition" data-tip="1655" target="_blank" href="/glossary-term/reciprocal-inhibition" class="glossary">reciprocal inhibition</a>). Several studies have demonstrated a decrease in <a id="antagonists" data-tip="1705" target="_blank" href="/glossary-term/antagonists" class="glossary">antagonist</a> activity and <a id="reciprocal-inhibition" data-tip="1655" target="_blank" href="/glossary-term/reciprocal-inhibition" class="glossary">reciprocal inhibition</a> (5, 8 - 10, 16, 20); in fact, a study by Hagbarth et al. demonstrated that simultaneous vibration of both agonist and <a id="antagonists" data-tip="1705" target="_blank" href="/glossary-term/antagonists" class="glossary">antagonist</a> resulted in inhibition of both muscles (5). The stimulation of stretch reflex and the effect vibration has on agonist activity is more complex, and not definitively understood. Studies demonstrate that vibration results in both the presynaptic inhibition of stretch reflex of the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> being vibrated (9, 12, 20), as well as a frequency matched increase in <a id="motor-unit" data-tip="1303" target="_blank" href="/glossary-term/motor-unit" class="glossary">motor unit</a> firing rate referred to as the tonic vibration reflex (TVR) (1, 2, 4-8, 11, 13- 20, 33). This is a contradictory set of findings, as presynaptic inhibition should result in a decrease in <a id="motor-unit" data-tip="1303" target="_blank" href="/glossary-term/motor-unit" class="glossary">motor unit</a> recruitment. Only a few references could be found exploring this contradiction (21 - 24), an older study by Gillies et al. (1969) offers two <a id="hypothesis" data-tip="1447" target="_blank" href="/glossary-term/hypothesis" class="glossary">hypotheses</a> (21):
<ul>
 <li>Vibration may lead to pre-synaptic inhibition, as well as volleys of Ia afferent stimulation that results in sufficient excitatory post-synaptic potentials to result in a tonic contraction. This <a id="hypothesis" data-tip="1446" target="_blank" href="/glossary-term/hypothesis" class="glossary">hypothesis</a> is supported further by Matthews et al. (23).</li>
 <li>Other types of tonic contractions, such as those exhibited by stroke patients, involve supraspinal structures. Vibration may stimulate a longer reflex arc that involves similar supraspinal structures, and results in motor <a id="nerve-cell" data-tip="1360" target="_blank" href="/glossary-term/nerve-cell" class="glossary">neuron</a> excitation despite pre-synaptic inhibition from Ia afferents. This <a id="hypothesis" data-tip="1446" target="_blank" href="/glossary-term/hypothesis" class="glossary">hypothesis</a> may be supported by research on central <a id="nervous-system" data-tip="1690" target="_blank" href="/glossary-term/nervous-system" class="glossary">nervous system</a> (CNS) involvement.
 <ul>
 <li>Note: These two <a id="hypothesis" data-tip="1447" target="_blank" href="/glossary-term/hypothesis" class="glossary">hypotheses</a> may both be correct, occurring simultaneously, contributing to some of the fluctuations in motor activity exhibited during the TVR (45).</li>
 </ul>
 </li>
</ul>
In summary, these studies suggest that local vibration results in simultaneous agonist inhibition, agonist tonic contraction (TVR), and <a id="reciprocal-inhibition" data-tip="1655" target="_blank" href="/glossary-term/reciprocal-inhibition" class="glossary">reciprocal inhibition</a> of the functional <a id="antagonists" data-tip="1705" target="_blank" href="/glossary-term/antagonists" class="glossary">antagonist</a>, which may have implications for using local vibration for rehabilitation or performance.
<h4>Summary</h4>
<ul>
 <li>Local vibration results in:
 <ul>
 <li>Inhibition of Agonist</li>
 <li>Activation of Agonist</li>
 <li>Inhibition of Antagonist</li>
 </ul>
 </li>
</ul>

The use of local vibration in practice may benefit from an understanding of the effect vibration has on reflexes. Specifically, the effect vibration has on the H-reflex (Hoffman&apos;s reflex) which is analogous to the stretch reflex but stimulated electrically, and the T-reflex (deep tendon reflex) which is stimulated by a tendon tap, such as the &quot;knee-jerk test&quot;. Arcangel et al. demonstrated that Achilles tendon vibration resulted in a decrease in the H-reflex and T-reflex, but in the post-vibratory period, the H-reflex stayed inhibited while the T- reflex was potentiated (17). Similar findings, using vibration on other muscles, have been demonstrated by other researchers (9, 20 - 25, 35). These findings are hypothesized to relate to the tonic and phasic aspects of stretch reflex; that is, they are the result of the inherent properties of the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindle/gamma afferent system. In practice, these results may suggest that vibration is capable of reducing <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> over-activity or <a id="tone" data-tip="1639" target="_blank" href="/glossary-term/tone" class="glossary">tone</a> (H-reflex <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>), without affecting the reactive component of stretch reflex (T-reflex) associated with the performance of sport and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> activities such as running and jumping.
<h4>Summary</h4>
<ul>
 <li>During Vibration
 <ul>
 <li>Inhibition of H-Reflex and T-Reflex</li>
 </ul>
 </li>
 <li>Post Vibration
 <ul>
 <li>Inhibition of H-Reflex and <a id="post-activation-potentiation" data-tip="1393" target="_blank" href="/glossary-term/post-activation-potentiation" class="glossary">potentiation</a> of T-Reflex</li>
 </ul>
 </li>
</ul>

Several studies have demonstrated that local vibration results in a response from the central <a id="nervous-system" data-tip="1690" target="_blank" href="/glossary-term/nervous-system" class="glossary">nervous system</a> (CNS). In the Gillies et al. study mentioned earlier, one <a id="hypothesis" data-tip="1446" target="_blank" href="/glossary-term/hypothesis" class="glossary">hypothesis</a> for the contrary findings of inhibition and activation was the potential for a longer reflex arc that included cortical involvement in tonic contraction (22). Studies referred to earlier by Eklund et al. and Bishop et al., and additional research by Burke et al., have demonstrated that conscious voluntary effort, the Jendrassik&apos;s maneuver (clasping and pulling the hands apart), and CNS <a id="excitability" data-tip="1310" target="_blank" href="/glossary-term/excitability" class="glossary">excitability</a> may influence the strength of contraction of a <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> being vibrated (4, 16, 27). More recent studies have used transcranial magnetic stimulation (TMS) to more directly infer cortical involvement. Steyvers et al. used TMS to demonstrate increases in corticospinal <a id="excitability" data-tip="1310" target="_blank" href="/glossary-term/excitability" class="glossary">excitability</a> related to both the vibrated agonist and non-vibrated antagonistic <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> (28). Kossev et al. demonstrated that a vibratory stimulus resulted in a crossed response, resulting in <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> evoked potentials (29). A study by Munte et al. suggests cortical involvement that may extend beyond primary sensory fields to include kinesthetic phenomena, demonstrating phasic highly-lateralized evoked potentials located in the vicinity of the central sulcus <a id="contralateral" data-tip="1549" target="_blank" href="/glossary-term/contralateral" class="glossary">contralateral</a> to the stimulated arm, and over the fronto-central regions (30). The contribution of vibration to kinesthesia (also referred to as proprioception and position sense in this research) is supported by additional studies. Goodwin et al. demonstrated that vibratory stimulus could result in illusions of movement, even when a static position was being held (31). <a id="roll" data-tip="1602" target="_blank" href="/glossary-term/roll" class="glossary">Roll</a> et al. demonstrated that local vibration at the ankle masked or abolished proprioceptive afferentation resulting in quantitatively erroneous proprioceptive messages concerning movement parameters (11). Kazai et al. demonstrated significant alterations to wrist position during extension and knee and foot position during step-ups when local vibration was applied to wrist muscles or thigh muscles. (32) And, Eklund et al. demonstrated that vibration was an additive stimulus to position sense during motion of the knee, resulting in consistent under-estimation or over-estimation of knee position (depending on vibrator placement) (33). Although increased afferentation from type II receptors may account for the altered position sense, it cannot account for the results demonstrated by TMS that infer cortical stimulation of brain centers involved in both <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activation and kinesthesia. Although more research is needed, these studies demonstrate that the CNS is involved in the perception and response to local vibration, including tonic contraction, inhibition of antagonists, and kinesthesia resulting from vibration.
<h4>Summary</h4>
<ul>
 <li>TVR can be influenced by conscious effort, being in an excited state, or the Jendrassik&apos;s maneuver.</li>
 <li>Local vibration results in cortical evoked potentials.</li>
 <li>Local vibration influences position sense, which may be explained by stimulation of type II receptors; however, cortical areas affiliated with kinesthesia also respond to stimulus.</li>
</ul>

A complete explanation of the body&apos;s response to local vibration may need to include a response from additional receptors. The mechanoreceptors found in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> and <a id="connective-tissue-cell" data-tip="1368" target="_blank" href="/glossary-term/connective-tissue-cell" class="glossary">connective tissue</a> (joint capsules, ligaments, tendons, fascia) include the previously mentioned <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindles and Golgi tendon organs, as well as Pacinian corpuscles, Ruffini endings, and free <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a> endings (36 - 42). Several studies on felines have demonstrated a relationship between these mechanoreceptors and reflexive changes to motor control. Solomonow et al. demonstrated that sustained stretch and creep of the lumbar fascia resulted in immediate and long-lasting hyper-excitability of the <a href="https://brookbushinstitute.com/article/multifidus" target="_blank" rel="noopener">multifidus</a> (38). Another study by Solomnow et al. demonstrated that resection of shoulder joint afferents resulted in changes in shoulder <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> electromyographic (EMG) activity (39). Freeman et al. performed a similar study, demonstrating persistent and <a id="specificity" data-tip="1224" target="_blank" href="/glossary-term/specificity" class="glossary">specific</a> changes in motor activity and gait post resection of feline knee joint afferents (40). A study by Ekholm et al. adds additional detail, demonstrating that increasing intra&#x2010;articular pressure or pinching the <a id="anterior" data-tip="1566" target="_blank" href="/glossary-term/anterior" class="glossary">anterior</a> aspect of the feline knee joint capsule resulted in inhibition of the knee extensors and facilitation of the knee flexors in both decerebrated and spinalized preparations. Further, activation of the receptors in the <a id="medial" data-tip="1568" target="_blank" href="/glossary-term/medial" class="glossary">medial</a> collateral ligament also produced flexor facilitation (41). Last, Homma et al. demonstrated receptor activity matching the anticipated response of Pacinian corpuscles following vibration of the <a href="https://brookbushinstitute.com/article/gastrocnemius-plantaris" target="_blank" rel="noopener">gastrocnemius</a> in decerebrate cats (42). In all of these studies, the experiment was followed by dissection and staining for mechanoreceptors of the involved tissues, demonstrating an abundance of free <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a> endings, as well as Pacinian corpuscles and Ruffini endings. Golgi tendon organs were found in ligamentous and tendinous tissue, but not in joint tissue or fascial sheaths. The results of these studies demonstrate that additional mechanoreceptors are intimately involved in motor control via reflex arcs. These reflex arcs are not dependent on supraspinal structures, as the decerebrated and spinalized preparations demonstrate. Although a few studies on human subjects are discussed below, more research is needed to better understand which of these receptors is specifically affected by vibration, and the <a id="specificity" data-tip="1224" target="_blank" href="/glossary-term/specificity" class="glossary">specific</a> effect each receptor type has on motor activity.
A few studies have been published on the human knee joint receptor stimulation and its effect on <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activity. In a review on knee joint receptors, Zimny et al. summarizes some of the research findings with this statement, &quot;Ruffini mechanoreceptors are believed to contribute mainly to maintenance of <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> <a id="tone" data-tip="1639" target="_blank" href="/glossary-term/tone" class="glossary">tone</a>, Pacinian corpuscles, and Golgi tendon organs are stimulated during movement, and free <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a> endings are generally nociceptors&quot;(43). Rutherford et al. demonstrated that <a id="effusion" data-tip="1459" target="_blank" href="/glossary-term/effusion" class="glossary">effusion</a> of the knee joint results in inhibition of the <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">quadriceps</a> (44). Another study by Kim et al. demonstrated significant increases in <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">vastus medialis</a> EMG activity following electric stimulation of the <a id="medial" data-tip="1568" target="_blank" href="/glossary-term/medial" class="glossary">medial</a> collateral ligament (MCL), and increases in <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">vastus lateralis</a> EMG activity following electric stimulation of the <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> collateral ligament (LCL) (45). Naliboff et al. demonstrated that a toothed roller resulted in a decrease in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> <a id="tension" data-tip="1229" target="_blank" href="/glossary-term/tension" class="glossary">tension</a> and increased sympathetic activation that may be consistent with a <a id="model" data-tip="1469" target="_blank" href="/glossary-term/model" class="glossary">model</a> of activation of Pacinian receptors (46). Pacinian corpuscles are of special interest, as they are fast-adapting receptors that respond to sudden changes in pressure and vibration. <a id="model" data-tip="1471" target="_blank" href="/glossary-term/model" class="glossary">Models</a> referred to by Zimny et al. and Noliboff et al. suggest that stimulation of Pacinian corpuscles may result in a decrease in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> <a id="tone" data-tip="1639" target="_blank" href="/glossary-term/tone" class="glossary">tone</a>. These additional studies imply that mechanoreceptors also play a significant role in motor control and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activity in humans, and considering what is currently known Pacinian corpuscles may play a special role in response to vibration. It may be prudent for future research on local vibration devices to investigate the effect vibration has on Pacinian corpuscles and the resulting effect on <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activity.
<h4>Summary</h4>
<ul>
 <li>Mechanoreceptors include <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindles, Golgi tendon organs, Pacinian corpuscles, Ruffini endings, and free <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a> endings.</li>
 <li>Stimulation of mechanoreceptors results in changes in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activity, likely through spinal reflex arcs.</li>
 <li>Pacinian corpuscles may be the additional mechanoreceptor most likely to respond to local vibration.</li>
</ul>
<a href="https://www.datocms-assets.com/25800/1649109893-vastus-lateralis-hypervolt.jpeg"><img src="https://www.datocms-assets.com/25800/1649109893-vastus-lateralis-hypervolt.jpeg"></a>

<ul>
 <li>Local vibration has been used to study sensory afferents and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> response since the 1960s.</li>
 <li>Studies have demonstrated that high-frequency vibration preferentially stimulates type Ia sensory afferents (dynamic <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindle), and results in much less stimulation of type Ib sensory afferents (Golgi tendon organ) and type II afferents (static <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> spindle afferents).</li>
 <li>Research suggests that length, stretch, and increased <a id="tension" data-tip="1229" target="_blank" href="/glossary-term/tension" class="glossary">tension</a> in the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> being vibrated increase facilitation of receptors, including type Ib and type II afferents.</li>
 <li>Local vibration results in simultaneous agonist inhibition and tonic contraction (known as the tonic vibration reflex or TVR), and <a id="reciprocal-inhibition" data-tip="1655" target="_blank" href="/glossary-term/reciprocal-inhibition" class="glossary">reciprocal inhibition</a> of the functional <a id="antagonists" data-tip="1705" target="_blank" href="/glossary-term/antagonists" class="glossary">antagonist</a>.</li>
 <li>Local vibration may result in a reduction in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> <a id="tone" data-tip="1639" target="_blank" href="/glossary-term/tone" class="glossary">tone</a> (H-reflex <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>) while potentiating the reactive component of stretch reflex (T-reflex) associated with the performance of sport and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> activities such as running and jumping.</li>
 <li>Studies demonstrate that the CNS is involved in agonist tonic contraction, inhibition of antagonists, and kinesthesia resulting from local vibration.</li>
 <li>Studies imply that additional mechanoreceptors (Pacinian corpuscles, Ruffini endings, free <a id="nerve-cell" data-tip="1361" target="_blank" href="/glossary-term/nerve-cell" class="glossary">nerve</a> endings) play a significant role in motor control and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activity and that Pacinian corpuscles are the receptor most likely to respond to local vibration.</li>
</ul>
<a href="https://www.datocms-assets.com/25800/1649110483-vibration-pectoralis.jpeg"><img src="https://www.datocms-assets.com/25800/1649110483-vibration-pectoralis.jpeg"></a>

Summary of Receptor Response to Local Vibration

Practical Application

Vibration may aid in preventing the inflammation and delayed onset <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> soreness (DOMS) that accompanies strenuous exercise, especially from eccentric contractions. Sahebazamani et al. demonstrated that the administration of vibration before a DOMS inducing exercise protocol for elbow flexors, resulted in a decrease in DOMS, increase in range of motion, and decrease in the circumference of flexors when compared to controls (48). Koeda et al. demonstrated similar findings by applying vibration before and two days after exercise (49). An additional study by Hakami et al. demonstrated similar findings using vibration on lower extremity muscles in a group of female athletes (50). In an RCT by Fuller et al., post-exercise vibration was found to be &quot;no more effective&quot; than conventional massage and stretching for reducing signs and symptoms associated with DOMS. However, this wording used by the researchers is suspect; it is just as accurate to say that vibration was as effective as stretching and massage when performed post-exercise (51). One potential benefit of vibration when compared to massage, is that vibration is easily self-administered. A study by Kim et al. compared pre-exercise vibration to post-exercise vibration and found that pre-exercise vibration was significantly more effective at reducing DOMS (52). These studies imply that pre-exercise local vibration may be protective, reducing the swelling, loss of range of motion, and pain commonly associated with DOMS.

The effects of pre-exercise vibration on DOMS are not limited to functional signs and pain, which may be influenced by patient/tester expectations (placebo effect). Several studies have demonstrated significant differences in chemical markers associated with DOMS and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> damage. The study mentioned above by Kim et al. demonstrated that creatine kinase (CK) levels were lowest in the pre-vibration group and that lactate
dehydrogenase (LDH) levels were lower in pre-and post-vibration groups than a control group that did the same workout protocol without vibration (52). Cochrane et al. demonstrated improved pain, range of motion, and lower CK levels at 24, 48, and 72 hours when compared to controls (53). Imtiyaz et al. demonstrated that massage and vibration had similar effects on pain, range of motion, and CK levels when compared to controls; however, vibration resulted in lower LDH and massage resulted in better recovery of strength (1RM) (54). Bakhtiary et al. demonstrated reduced CK levels, pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>, and attenuated the loss in strength exhibited after downhill walking (55). Broadbent et al. adds the effect on additional markers associated with DOMS, demonstrating vibration reduced pain, as well as decreased interleukin 6 (IL6), decreased histamine, increased neutrophils, and decreased lymphocytes (56). Lau et al. was the only study that could be found that did not demonstrate a positive effect on chemical markers, and the vibration intervention was administered after exercise (57). This may imply that vibration only impacts chemical markers when done prior to exercise, as was the case in the other studies mentioned (52 - 56). These studies demonstrate that pre-exercise vibration decreases functional signs of DOMS, as well as attenuates chemical markers including decreased CK, LDH, IL6, histamine, lymphocytes, and increased neutrophils.

Vibration may also be used directly to reduce acute <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> pain. Ayles et al. demonstrated that when <a id="compression" data-tip="1595" target="_blank" href="/glossary-term/compression" class="glossary">compression</a> was applied to muscles affected by a DOMS inducing protocol pain increased; however when pressure and vibration were applied to the <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> pain decreased (58). The inhibition of <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> pain from local vibration may be more directly implied by a study by Weerakkody et al., which noted the same relationship between pain, <a id="compression" data-tip="1595" target="_blank" href="/glossary-term/compression" class="glossary">compression</a>, and vibration as Ayles., but induced pain by injecting saline solution into a <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> (59). In an RCT by Guieu et al., the combination of vibration and TENS was more effective for alleviating pain (reducing pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>) than either TENS or vibration alone (60). The combination of these two modalities is interesting, considering multiple researchers (58 - 60) have hypothesized that both TENS and vibration reduce pain via the same mechanism, the GAIT theory of pain control. Direct application of vibration may not be considered a viable &quot;treatment for pain&quot; until studies have demonstrated carry-over; however, vibration may have benefits for acutely addressing <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> pain. Addressing acute <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> pain may aid in self-management, as direct application of local vibration is available to patients for home use with tools like the Hypervolt by Hyperice&#xAE; used in our video.
<h4>Summary</h4>
<ul>
 <li>Pre-exercise local vibration may be protective, reducing swelling, improving range of motion, and decreasing pain associated with DOMS.</li>
 <li>Pre-exercise vibration attenuates chemical markers associated with DOMS including decreased CK, LDH, IL6, histamine, lymphocytes, and increased neutrophils.</li>
 <li>Direct application of vibration may have benefits for addressing acute <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> pain (and can be added to a home program via the Hypervolt or similar devices).</li>
</ul>

The effect of local vibration on <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> endurance, strength and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> is nuanced, but is fairly congruent with the effects on receptor activity and the tonic vibration reflex (TVR) discussed above.

Effect on Muscle Performance

Several studies have demonstrated that local vibration alone may be sufficient to increase strength in deconditioned lower extremity muscles. Pietrangelo et al. demonstrated that 12 weeks vibration of training (initially 15 min./week progressing to 15 min/3 times per week) in a group of elderly (65+) individuals diagnosed with sarcopenia enhanced maximal isometric strength (MVIC) and increased the percentage of type IIx myosin (61). An RCT by Rabini et al. demonstrated that 4 weeks of local vibration to <a href="https://brookbushinstitute.com/article/knee" target="_blank" rel="noopener">knee</a> muscles improved function of individuals diagnosed with mild to moderate knee osteoarthritis (62). Iodice et al. demonstrated that a group of young healthy males without previous exercise experience demonstrated increased levels of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> and creatine phosphokinase, decreased levels of cortisol, and increased MVIC with 4 weeks of local vibration training protocol (when compared to sedentary controls) (63). The increase in strength, function, and performance noted in these studies may be the result of introducing a contraction stimulus via the tonic vibration reflex (TVR). The ability of local vibration to increase strength without weight-bearing may be particularly beneficial in a rehab setting. Note, the Brookbush Institute does not recommend using local vibration training as a replacement for resistance training in young healthy individuals.

Pre-exercise local vibration may be beneficial for enhancing training: however, the protocol used should be considered. Koh et al. demonstrated that pre-exercise local vibration improved maximal voluntary isometric (MVIC) contraction strength when tested on subsequent days (64). Further, studies by Hakami et al. and Bakhtiari et al. demonstrated enhanced performance in subsequent workouts, when running and sport was preceded by local vibration (50, 55). These findings likely can be attributed to the &quot;protection from DOMS&quot; discussed above. Conversely, long-duration (10 - 30 minutes/muscle), pre-exercise local vibration should be avoided and may be detrimental to performance. Jackson et al. demonstrated that prolonged local vibration to the <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">quadriceps</a> reduced knee extension MVIC (65). Mottram et al. demonstrated prolonged local vibration to the biceps brachii tendon reduced subsequent <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> endurance (66). A suggestion for length may be implied by a study by Otadi et al., which demonstrated that 2 minutes of pre-exercise local vibration increased <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">quadriceps</a> MVIC and time to fatigue (84). Note, an additional study by Souron et al. suggests 2 minutes of pre-exercise local vibration may not have the same effect on <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> activities (85). These studies suggest that long duration (10+ min./muscle) pre-exercise local vibration should be avoided as it may be detrimental to performance; however, short duration (2 min./muscle) local vibration may enhance strength and performance in subsequent workouts. Note, the Brookbush Institute recommends 30 seconds to 2 minutes per <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> group and no more than 5 minutes per <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> - even in cases of muscles with multiple <a id="trigger-point" data-tip="1634" target="_blank" href="/glossary-term/trigger-point" class="glossary">trigger points</a>.
<a href="https://www.datocms-assets.com/25800/1649110935-vibration-adductors.jpeg"><img src="https://www.datocms-assets.com/25800/1649110935-vibration-adductors.jpeg"></a>

Direct application of local vibration during resistance training has a nuanced effect on <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> performance, and results from the following studies suggest that the competing inhibition and TVR resulting from polysynaptic stimulation of type Ia afferents may be involved. Samuelson et al. demonstrated local vibration during leg extensions had a negative impact on knee extensor <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> endurance (67). Bosco et al. demonstrated that the mean <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> of wrist flexors during 5 concentric contractions with vibration was enhanced in 12 international boxers (68). Gabriel et al. demonstrated that local vibration applied to the triceps tendon improved subsequent performance in a pre-fatigued <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> (69). Warman et al. demonstrated local vibration increased wrist extension torque; however, only during concentric contractions, and not during isometric or isokinetic contractions (70). Souron et al. demonstrated that local vibration applied directly to the tendon at mid-length of the <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">quadriceps</a> increased <a id="motor-unit" data-tip="1303" target="_blank" href="/glossary-term/motor-unit" class="glossary">motor unit</a> recruitment (86). These very nuanced findings can be explained by the addition of TVR to voluntary contractions in conjunction with pre-synaptic inhibition of <a id="prime-mover" data-tip="1664" target="_blank" href="/glossary-term/prime-mover" class="glossary">agonists</a>. That is, an increase in the initial number of motor units would have a negative impact on endurance, but a positive impact on concentric sub-maximal force production, force production from a <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> losing <a id="motor-unit" data-tip="1303" target="_blank" href="/glossary-term/motor-unit" class="glossary">motor unit</a> recruitment to fatigue, and an experimental condition in which the <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> amount of recruitment from volitional contraction and vibration was achieved. Conversely, local vibration may benefit <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> performance that requires maximal <a id="motor-unit" data-tip="1303" target="_blank" href="/glossary-term/motor-unit" class="glossary">motor unit</a> recruitment (e.g. MVIC, isometric, and isokinetic tests), or intra-muscular coordination, due to the limitation imposed by presynaptic inhibition and the reflexive recruitment as a result of TVR.

The use of wearable local vibration technology during strength training is likely not beneficial; however, some benefit may be gained for individuals training for <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>. Drummond et al. compared the effects of 12 weeks of conventional dynamic strength training to the same program with the addition of local vibration on previously untrained individuals. The study demonstrated no significant difference between the two groups (71). Goebel et al. demonstrated that curls with vibration resulted in a larger increase in isometric strength than curls without vibration; however, the load used (70% 1RM) was relatively light (83). It might be hypothesized that at this lighter weight, vibration may increase <a id="motor-unit" data-tip="1303" target="_blank" href="/glossary-term/motor-unit" class="glossary">motor unit</a> recruitment, but that the increase would not have occurred if the load was larger. Issurin et al. demonstrated that muscles vibrated while working out resulted in an increase in mean and maximal <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> for amateur athletes, and increased maximal <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> for elite athletes; however, there was no residual effect (72). The Issurin et al. study likely implies that local vibration would be a good training aid for <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, but any benefit would have to be the result of adaptation to the increases in performance during training sessions. Further study to refine protocols is likely warranted, as an additional study by Ivanenko et al. demonstrated significant differences in performance (walking speed) during the application of various vibration protocols on thigh muscles while walking (73). These studies imply that the application of local vibration while training may be beneficial for <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> training but not strength training. These findings may be due to the combination of H-reflex inhibition, T-reflex <a id="post-activation-potentiation" data-tip="1393" target="_blank" href="/glossary-term/post-activation-potentiation" class="glossary">potentiation</a>, and presynaptic inhibition of <a id="motor-unit" data-tip="1303" target="_blank" href="/glossary-term/motor-unit" class="glossary">motor unit</a> recruitment. Considering the fairly limited potential use (only for <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> training), the lack of residual effect, the difficulties of applying local vibration while training, and the potential of wearable technology being uncomfortable during ballistic movements, further research is recommended before adoption of local vibration in performance programming.
<a href="https://www.datocms-assets.com/25800/1649111137-rhomboid-sa-release.jpeg"><img src="https://www.datocms-assets.com/25800/1649111137-rhomboid-sa-release.jpeg"></a>
Comparing Foam Rollers to Vibrating Foam Rollers
Recently a new application of local vibration has entered the market; devices that add vibration to foam rolls and spheres for self-myofascial <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> (SMR). To date, all of these studies have investigated the effects of vibration added to foam rolling on lower extremity muscles. In an RCT by Cheatham et al., the vibrating foam <a id="roll" data-tip="1602" target="_blank" href="/glossary-term/roll" class="glossary">roll</a> (VFR) group demonstrated larger decreases in pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a> than the conventional foam rolling group (FR) and nearly achieved statistically <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> increases in range of motion (74). A study by Han et al. compared VFR to FR for muscles around the <a href="https://brookbushinstitute.com/article/hip-joint" target="_blank" rel="noopener">hip</a>, demonstrating that VFR resulted in a significant increase in <a href="https://brookbushinstitute.com/article/hip-joint" target="_blank" rel="noopener">hip</a> flexion and internal rotation range of motion (75). Romero et al. demonstrated that after a DOMS inducing workout that greater short-term benefits in pain perception and passive extension hip joint ROM were achieved with VFR, and both VFR and FR improved pain pressure threshold, <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> oxygen saturation, jump height, and knee joint range of motion (76). Further, in an RCT by Lee et al. warming-up with VFR resulted in similar increases in <a id="mobility" data-tip="1455" target="_blank" href="/glossary-term/mobility" class="glossary">mobility</a> as FR or stretching, but significantly better <a href="https://brookbushinstitute.com/article/knee" target="_blank" rel="noopener">knee</a> joint reposition <a id="accuracy" data-tip="1218" target="_blank" href="/glossary-term/accuracy" class="glossary">accuracy</a>, dynamic <a id="balance" data-tip="1190" target="_blank" href="/glossary-term/balance" class="glossary">balance</a> (proprioception), and <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">quadriceps</a> <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> strength (77). Two studies have failed to demonstrate significant differences between VFR and FR. Garcia-Guti&#xE9;rrez et al. demonstrated that VFR and FR for <a href="https://brookbushinstitute.com/article/gastrocnemius-plantaris" target="_blank" rel="noopener">calf muscles</a> resulted in similar improvements in <a href="https://brookbushinstitute.com/article/ankle-joint-talocrural-subtalar-tibiofibular-joints" target="_blank" rel="noopener">ankle</a> dorsiflexion range of motion (78), and Sa&#x11F;iro&#x11F;lu et al. demonstrated that VFR and FR resulted in similar improvements in range of motion and jump height (79). These studies suggest that adding vibration to foam rolling has a significant effect on some, but not all benefits associated with foam rolling and self-administered <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a>. The inconsistencies between studies likely suggest that more research is needed to refine protocols, and determine the best uses for VFR. Currently, research implies that vibration added to foam rolling has a significant effect on DOMS, pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>, and proprioception, and further research is needed to determine the potential benefits for a range of motion and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> performance when used as a warm-up.

Recently a new application of local vibration has entered the market; devices that add vibration to foam rolls and spheres for self-myofascial <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> (SMR). To date, all of these studies have investigated the effects of vibration added to foam rolling on lower extremity muscles. In an RCT by Cheatham et al., the vibrating foam <a id="roll" data-tip="1602" target="_blank" href="/glossary-term/roll" class="glossary">roll</a> (VFR) group demonstrated larger decreases in pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a> than the conventional foam rolling group (FR) and nearly achieved statistically <a id="superior" data-tip="1570" target="_blank" href="/glossary-term/superior" class="glossary">superior</a> increases in range of motion (74). A study by Han et al. compared VFR to FR for muscles around the <a href="https://brookbushinstitute.com/article/hip-joint" target="_blank" rel="noopener">hip</a>, demonstrating that VFR resulted in a significant increase in <a href="https://brookbushinstitute.com/article/hip-joint" target="_blank" rel="noopener">hip</a> flexion and internal rotation range of motion (75). Romero et al. demonstrated that after a DOMS inducing workout that greater short-term benefits in pain perception and passive extension hip joint ROM were achieved with VFR, and both VFR and FR improved pain pressure threshold, <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> oxygen saturation, jump height, and knee joint range of motion (76). Further, in an RCT by Lee et al. warming up with VFR resulted in similar increases in <a id="mobility" data-tip="1455" target="_blank" href="/glossary-term/mobility" class="glossary">mobility</a> as FR or stretching, but significantly better <a href="https://brookbushinstitute.com/article/knee" target="_blank" rel="noopener">knee</a> joint reposition <a id="accuracy" data-tip="1218" target="_blank" href="/glossary-term/accuracy" class="glossary">accuracy</a>, dynamic <a id="balance" data-tip="1190" target="_blank" href="/glossary-term/balance" class="glossary">balance</a> (proprioception), and <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">quadriceps</a> <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> strength (77). Two studies have failed to demonstrate significant differences between VFR and FR. Garcia-Guti&#xE9;rrez et al. demonstrated that VFR and FR for <a href="https://brookbushinstitute.com/article/gastrocnemius-plantaris" target="_blank" rel="noopener">calf muscles</a> resulted in similar improvements in <a href="https://brookbushinstitute.com/article/ankle-joint-talocrural-subtalar-tibiofibular-joints" target="_blank" rel="noopener">ankle</a> dorsiflexion range of motion (78), and Sa&#x11F;iro&#x11F;lu et al. demonstrated that VFR and FR resulted in similar improvements in range of motion and jump height (79). These studies suggest that adding vibration to foam rolling has a significant effect on some, but not all benefits associated with foam rolling and self-administered <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a>. The inconsistencies between studies likely suggest that more research is needed to refine protocols, and determine the best uses for VFR. Currently, research implies that vibration added to foam rolling has a significant effect on DOMS, pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>, and proprioception, and further research is needed to determine the potential benefits for a range of motion and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> performance when used as a warm-up.
<h4>Local Vibration During Stretching</h4>
Three studies have demonstrated that adding local vibration to static stretching results in further increases in <a id="mobility" data-tip="1455" target="_blank" href="/glossary-term/mobility" class="glossary">mobility</a>. Sands et al. demonstrated that a 4-week program of stretching with vibration significantly increased range of motion when compared to a 4-week static stretching program, in highly trained male gymnasts (80). A study by Cronin et al. demonstrated that a single bout of hamstring stretching with vibration was more effective than stretching for improving <a href="https://brookbushinstitute.com/article/knee" target="_blank" rel="noopener">knee</a> joint range of motion (81). A study by Peer et al. demonstrated that stretching with vibration was effective for improving <a href="https://brookbushinstitute.com/article/ankle-joint-talocrural-subtalar-tibiofibular-joints" target="_blank" rel="noopener">ankle</a> range of motion post <a href="https://brookbushinstitute.com/article/ankle-joint-talocrural-subtalar-tibiofibular-joints" target="_blank" rel="noopener">ankle</a> sprain, but no comparison group was used in this study (82). The Brookbush Institute recommends that local vibration (vibration <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques) is used prior to lengthening techniques; however, these studies suggest that there may be some benefit to incorporating local vibration while stretching.

<h4>Summary</h4>
<ul>
 <li>Local vibration alone may be sufficient to increase strength in deconditioned muscles/individuals.</li>
 <li>Long duration (10+ min./muscle) pre-exercise local vibration should be avoided as it may be detrimental to performance; however, short duration (2 min./muscle) local vibration may enhance strength and performance in subsequent workouts.</li>
 <li>The application of pre-exercise local vibration should be limited to less than 10 minutes per <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a>. (The Brookbush Institute protocols suggest 1 - 2 minutes per muscles and no more than 5 minutes)</li>
 <li>The application of local vibration during training may attenuate sub-maximal concentric strength and maximal power; however, the limited benefit, lack of residual effect, and practical issues with wearing vibration technology warrant further study before use in strength and performance settings can be recommended. (Reminder, this is a statement based on studies investigating the direct application of vibration to muscles being trained, and does not include whole body vibration research)</li>
 <li>Currently, research implies that vibration added to foam rolling has a significant effect on DOMS, pain pressure <a id="sensitivity" data-tip="1226" target="_blank" href="/glossary-term/sensitivity" class="glossary">sensitivity</a>, and proprioception, and further research is needed to determine the potential benefits for range of motion and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> performance when used as a warm-up.</li>
 <li>The Brookbush Institute recommends that local vibration (vibration <a id="release" data-tip="1249" target="_blank" href="/glossary-term/release" class="glossary">release</a> techniques) is used prior to lengthening techniques; however, these studies suggest that there may be some benefit to incorporating local vibration while stretching.</li>
</ul>

Summary of Effects on Muscle Performance

Bibliobraphy

© 2019 Brent Brookbush
Questions, comments, and criticisms are welcomed and encouraged -

Copyright

A-Band - Refers to the part of the muscle cell that looks darker under a microscope.  This area of the cell is darker due to parallel arrangement of thicker filaments (myosin) and overlap with the thinner filaments (actin).
<ul>
 	<li>As a muscle contracts, the A-band is where actin and myosin interact.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Accuracy - the proportion of individuals correctly identified by the test results.
<ul>
 	<li>For example, a special test with perfect accuracy would imply a test has 100% specificity, 100% sensitivity, 100% positive predictive value and 100% negative predictive values.</li>
</ul>

Action Potential - A rapid change in voltage, resulting in a wave of excitation, that may result in stimulation of a nerve or muscle cell.
<ul>
 	<li>In order for an action potential to be initiated, the resting membrane voltage must exceed the excitation threshold, which then results in a cascade of depolarization and the "wave of excitation." Any stimulus below that threshold will not result in an action potential, and a stimulus greater than the threshold will not increase a single action potential, but may result in additional action potentials.  In this way, the action potential functions more like an on/off switch (all or none), and less like a dimmer switch.</li>
</ul>

A single-joint movement pattern (most often) designed to load a specific under-active muscle(s), while minimizing the contribution of over-active synergists via specific cues/joint motions.
<ul>
 	<li style="text-align: left;">Activation techniques/exercises are performed with the intent of addressing a muscle exhibiting a reduction in activity (tone) as a result of, or contributing to postural dysfunction.</li>
 	<li style="text-align: left;">Activation techniques/exercises cannot be multi-joint movement patterns due to relative flexibility, altered reciprocal inhibition, and synergistic dominance resulting in compensation patterns.</li>
</ul>
Example, <a href="https://brentbrookbush.com/articles/corrective-exercise-articles/activation/gluteus-medius-activation-progression/" target="_blank">gluteus medius activation</a> involves resisted hip abduction while minimizing the contribution of the TFL via hip extension.

Active stretching is a term used to describe a stretch that involves an active contraction of opposing musculature to lengthen a muscle to its end range. Generally these stretches are held for 2-5 seconds and repeated for 8-15 repetitions.

Adenosine triphosphatase (ATPase): is the enzyme responsible for catalyzing (initiating and accelerating) the decomposition of ATP to ADP.
<ul>
 	<li>This dephosphorylation (breakdown) reaction releases energy for processes like muscular contraction.</li>
</ul>

Adenosine triphosphate (ATP): The molecule that functions as a universal energy-transfer molecule, providing most of the energy associated with muscular contraction and human movement. ATP is composed of an adenine group, a ribose group, and three molecules of inorganic phosphates.
<ul>
 	<li>Energy is provided when hydrolysis results in the cleaving of a phophate group; resulting in adenosine diphosphate, an inorganigic phosphate group, and energy.</li>
</ul>

Algometry - measuring the amount of pressure to result in sensitivity or pain, using an algometer.
<ul>
 	<li>Generally, research uses algometry to establish a minimum pain pressure threshold (PPT), in which a lower PPT implies more sensitivity and pain, and a higher PPT implies less sensitivity and pain. PPT is a common outcome measure in trigger point research.</li>
</ul>
<a href="https://brentbrookbush.com/wp-content/uploads/2019/07/Algometer.jpg"><img class="aligncenter wp-image-140177" src="https://brentbrookbush.com/wp-content/uploads/2019/07/Algometer.jpg" alt="Image of an Algometer" width="500" height="333" /></a>

All-or-none principle - a nerve or muscle cell's response to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential (threshold of an action potential), the nerve or muscle fiber will respond completely; otherwise, there is no response.

Example, when a motor unit in the biceps brachii is stimulated it contracts the same way whether a 10 lb or 50 lb dumbbell is lifted.  It is actually the number of muscle cells and the size of the motor unit that determines force output.

&nbsp;

The transition period between eccentric load and concentric contraction during a repetition of an exercise.  This term is most often used in reference to power/plyometric exercises, in which a shorter amortization phase is believed to be beneficial.  The shorter amortization phase may better use the stored energy from the elastic deformation of connective tissue and enhance synchronization of myotatic (stretch) reflex with maximum voluntary contraction.

Example, the athlete was cued to spend as little time as possible in the bottom of their squat stance (the amortization phase) during a set of box jumps.

Muscles that oppose the prime mover and synergists for a given joint action.

That is, all the muscles that can perform the opposing joint action.

Example: The triceps and anconeus are antagonists during elbow flexion.

An anatomical direction; toward the front

Example, the face is on the anterior aspect of the head

Appendicular Skeleton - referring to the bones the bones of the arms and legs, as well as the bones that support them. This includes the pelvis, clavicle and scapula. There are approximately 126 bones in the appendicular skeleton.
<ul>
 	<li>Etymology - Appendicular, as in appendage, "that which is appended to something as a proper part," 1640s, from <a class="crossreference" href="https://www.etymonline.com/word/append?ref=etymonline_crossreference">append</a> + <a class="crossreference" href="https://www.etymonline.com/word/-age?ref=etymonline_crossreference">-age</a>. - <a href="https://www.etymonline.com/word/appendage" target="_blank" rel="noopener">Etymology Online</a></li>
</ul>
"Appendicular skeleton" is a label referring to a set of bones whose function is distinct from the bones of the "<a href="https://brentbrookbush.com/glossary/axial-skeleton/" target="_blank" rel="noopener">axial skeleton</a>".

A reflexive decrease in muscle activity due to joint dyskinesis.
For example, a reduction in deep cervical flexor activity as a result of cervical spine dyskinesis.

Arthrokinematic Motion - Small amplitude motions between bone surfaces at a joint.  The arthrokinematic motions are roll, glide (slide or translation), spin, compression and distraction (traction). Arthrokinematic motions accompany osteokinematic motions to maintain joint congruence.
<ul>
 	<li>Example, arthrokinematic motion of the talus includes posterior glide on the tibia during ankle dorsiflexion.</li>
</ul>
Synonyms include: arthrokinematics, passive accessory motion, joint play and component motion

&nbsp;

Assessment - is the act of assessing, i.e. determining the importance, size, or value of -

In most cases, the results of an assessment are compared to normative data. If the individual exhibits values that are within normal parameters, it may be assumed that the aspect of health or motion assessed is not contributing to the patient's complaint, symptoms or movement impairment. If the results fall outside of normal parameters, it may indicate that the aspect of health or motion assessed is contributing to, or being affected by the patient/client's complaint, symptoms, or movement impairment. In some cases, the results of an assessment are compared to an "ideal model." In this case, deviations from the ideal are noted as potential issues. For example, deviations noted in the <a title="Introduction to the Overhead Squat Assessment" href="https://brentbrookbush.com/online-courses/articles/assessment/introduction-overhead-squat-assessment/" target="_blank">Overhead Squat Assessment</a> are compared to an "ideal model" of posture and motion.

Assessments used by human movement professionals can be divided into three broad categories:
<ul>
 	<li>"Clear" the Patient/Client for Intervention - These are tests, assessments and evaluations used to determine if a patient/client's issue may improve given the assessing professional's scope, skills, abilities and willingness to treat that individual.
<ul>
 	<li>For example, many of the special tests used in orthopedic medicine assist in determining the level of pathology or likelihood of a particular diagnosis. Certain issues and diagnoses are beyond the scope of the human movement professional, and are better treated by diagnostic professionals in the medical community (physicians, podiatrists, surgeons, etc.). A Calf Squeeze (Thompson) Test is one example, in which a positive sign may indicate a rupture of the Achilles tendon that may be better treated via surgical intervention.</li>
</ul>
</li>
 	<li>Highlight Contraindications - Tests, assessments and evaluations used to stratify risk or preclude a professional from addressing certain tissues, motions or using a particular technique.
<ul>
 	<li>For example, the Vertebral Artery Test (VBI) is often used to determine if high velocity thrust mobilizations (manipulations) are safe for a patient with cervical dysfunction.</li>
</ul>
</li>
 	<li>Refine Exercise/Intervention Selection: Tests, assessments and evaluations used to assist the professional in determining which techniques, modalities and exercises will best address a patient/client's complaints or desired goals.
<ul>
 	<li>Most movement assessments fall into this category. For example, a positive <a href="https://brentbrookbush.com/vimeo_videos/elys-test-rectus-femoris-flexibility-assessment/" target="_blank">Ely's Test</a> may indicate a need to release and/or lengthen the <a href="https://brentbrookbush.com/articles/anatomy-articles/muscular-anatomy/rectus-femoris/" target="_blank">rectus femoris</a>.</li>
</ul>
</li>
</ul>
Note: An assessment, or assessment result, may fall into more than one category. For example, although goniometry is an assessment most often used to Refine Exercise/Intervention Selection, if a range of motion is significantly altered, with an abnormal end-feel, and/or causes the patient or client/pain, the individual may need to be referred to a physician for further testing and Clearance to resume rehab activities.  Further, that same patient may return to the human movement professional with a list of Contraindicated Activities from the physician. - "When in doubt, refer out!"

Axial Skeleton - referring to the bones of the head, neck, trunk and spinal column (does not include pelvis). There are approximately 80 bones in the axial skeleton.
<ul>
 	<li>Etymology - Axial, as in "axis", referring to "imaginary motionless straight line around which a body (such as the Earth) rotates," from Latin axis "axle, pivot, axis of the earth or sky" - <a href="https://www.etymonline.com/word/axis" target="_blank" rel="noopener">Etymology Online</a></li>
</ul>
"Axial skeleton" is a label referring to a set of bones whose function is distinct from the bones of the "<a href="https://brentbrookbush.com/glossary/appendicular-skeleton/" target="_blank" rel="noopener">appendicular skeleton</a>".

Balance - The ability to maintain a body’s center of mass over its base of support. Balance can be static or dynamic.
<ul>
 	<li>For example, maintaining balance is harder on one leg because the center of mass must stay over a much smaller base of support.</li>
</ul>

A ball and socket joint (also called a spheroid joint or spheroidal joint) is a synovial joint in which the rounded or spherical end of one bone fits into a cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of axes, which have one common center. Examples include the hip and shoulder (glenohumeral joint)

Base of support (BoS) - refers to the area beneath an object or person, and the area within the perimeter created by every point of contact that the object or person makes with the supporting surface. This may include the <a href="https://brentbrookbush.com/articles/anatomy-articles/muscular-anatomy/gluteus-maximus/" target="_blank" rel="noopener">glutes</a> of someone sitting on a chair, or the back of someone leaning against a wall.
<ul>
 	<li>For example, during a single leg balance the BoS is the area of the foot in contact with the surface; however, when a person is standing on two feet, the BoS is the area of both feet and the surface between them.</li>
</ul>

Pertaining to both sides

Example, bilateral rows are performed with both arms at the same time.

Case-control Study - a particular form of retrospective study that samples a matched group of people who have, and do not have the outcome being studied. A case-control study is a quasi-experimental design, often used in medicine to aid in determining potential contributing factors (cannot determine causality). In this study type exposure is the dependent variable and outcome is independent.
<ul>
 	<li>Example, in this retrospective case-control, medical records were investigated for trends correlated with cervical pain (1).
<ol>
 	<li>Mäkela, M., Heliövaara, M., Sievers, K., Impivaara, O., Knekt, P., &amp; Aromaa, A. (1991). Prevalence, determinants, and consequences of chronic neck pain in Finland. American journal of epidemiology, 134(11), 1356-1367.</li>
</ol>
</li>
</ul>

An anatomical direction; toward the tail, relative to humans this term is often used to refer to "in the direction of the tale (toward the feet)".

Example, to release the trapezius muscle the therapist used a force directed caudally.

Center of mass (CoM) - an object's mean position of mass; that is, a point that is perfectly surrounded by an equal amount mass in all directions.

Center of gravity (CoG) - point where gravity appears to act. Since the human body is so small compared to the earth, we can assume gravity acts uniformly on the body, and that CoG and CoM are the same.
<ul>
 	<li>Example, the CoM of the human body while lying down or standing straight up is close to our navel. However, it is possible that during a resistance exercise, the combination of the body's weight and the weight of the resistance will place the combined CoM outside the body. For example, during the mid-portion of a <a href="https://brentbrookbush.com/vimeo_videos/back-squat/" target="_blank" rel="noopener">back squat</a> the CoM would be several anterior to the naval.</li>
</ul>

An anatomical direction; toward the head (synonym: cranial)

Example, hip pain was felt with any force directed cephalad.

Cohort Study - a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic), performing a cross-section at intervals through-out a period of time. A cohort study is a quasi-experimental design often used in medicine to aid in determining etiology or a cause-and-effect relationship. In this study type exposure is the independent variable and outcome is dependent.
<ul>
 	<li>Example, the study by Cholewicki et al. (1) investigated Yale Varsity Athletes (the cohort) with 2 and 3 year follow up (longitudinal design) and found that trunk muscle response time to off-loading was predictive of future low back injury.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/core/increased-trunk-muscle-latency-may-cause-rather-than-result-from-low-back-pain/" target="_blank" rel="noopener noreferrer">Cholewicki, J., Silfies, S., Shah, R., Greene, H., Reeves, N. Alvi, K., Goldberg, B. (2005). Delayed trunk muscle reflex responses increase the risk of low back injuries. Spine. 30(23), 2614-2620</a></li>
</ol>

Comparable Sign: A combination of pain, stiffness and/or spasm during examination that is comparable to the patients symptoms.
<ul>
 	<li>One common error made during evaluation with special tests is attention given to any discomfort or pain, rather than attempting to identify the pain/discomfort related to the patient's complaint (concordant/comparable sign). Many special tests purposefully test tissue limits and are at least mildly uncomfortable in every individual. Basing your assessment on positive tests that resulted in "concordant/comparable signs" will improve your chances of arriving at the correct diagnosis.</li>
</ul>

An alternative movement pattern that has been adopted to compensate for dysfunction/impairment in the human movement system.
Example: A lack of calf extensibility may limit dorsiflexion, leading to the knees bowing inward (functional valgus) and excessive forward lean of the torso during a squat.

An arthrokinematic motion - the approximation of joint surfaces; that is, a force that directs one bone surface into another resulting in a reduction in intra-articular volume. Although widely thought of as a "destructive force", it is likely best to consider compression as a naturally occurring, stabilizing force. Any arthrokinematic force in excess (spin, glide, roll, traction) may be viewed as potentially deleterious.

For example, during a squat the femoral head is compressed into the acetabulum by muscular forces, bodyweight and any additional external load.

Concave (Concavity) - Having an outline or surface curved like the interior surface of a bowl or sphere - to cave-in or curve inward.
<ul>
 	<li>Example, the internal surfaces of the pelvis is concave, holding some of the bodies viscera.</li>
</ul>

Concordant Sign - The patient's specific pain, symptom or complaint. 
<ul>
 	<li>One common error made during evaluation with special tests is attention given to any discomfort or pain, rather than attempting to identify the pain/discomfort related to the patient's complaint (concordant/comparable sign). Many special tests purposefully test tissue limits and are at least mildly uncomfortable in every individual. Basing your assessment on positive tests that resulted in "concordant/comparable signs" will improve your chances of arriving at the correct diagnosis.</li>
</ul>

Conductivity: Stimulation results in more than a local effect (1).
<ul>
 	<li>For example, in a muscle cell the stimulation of a motor endplate results in a change in cell membrane polarity that rapidly propagates (is conducted) along the entire length of the muscle cell, stimulating all sacromere.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

A condyloid joint (also called condylar, bicondylar, ellipsoid, or ellipsoidal) is an ovoid articular surface, or condyle, that is received into an elliptical cavity.  These joints permit movement in two planes.  Examples include the knee, metacarpophalangeal joints and metatarsophalangeal joints.

Connective Tissue Cell - One of the four basic types of animal tissue, consisting mostly fibers and ground substance.  These cells are specialized to binds organs together, holds them in place, protect them from external forces, and may fill space in the body's cavities.

Example, the body's muscles are enclosed in durable connective tissue sheets known as the "epimysium", "perimysium", and "endomysium," which and in support and transmitting force.
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Contractility: The ability to shorten (1).
<ul>
 	<li>Contractility: Muscle cells are unique in the amount they can shorten when stimulated; this is this largerly due to the highly organized and unique arrangement of myofilaments (actin and myosin).</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Pertaining to the opposite side

Example, the external oblique muscle performs contralateral rotation; rotation to the opposite side.

Convex (Convexity) - Having an outline or surface curved like the exterior of a circle or sphere - to bulge or curve outward.
<ul>
 	<li>Example, the top of your head is shaped by the convex exterior surface of your skull.</li>
</ul>

Correlational Research - Non-experimental <a href="https://www.questionpro.com/blog/what-is-research/">research</a> method in which the statistical relationship between two variables is investigated.
<ul>
 	<li>In this research by Kwon et al., a correlation was noted between a decrease in extensibility during a hamstring length test (goniometry) and current knee pain (1).</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/correlation-patellofemoral-pain-syndrome-pfps-hamstring-activity/" target="_blank" rel="noopener">Kwon O, Yun M, and Lee W. (2014). Correlation between intrinsic patellofemoral pain syndrome in young adults and lower extremity biomechanics. J. Phys. Ther. Sci. 26: 961-964</a></li>
</ol>

Counter-nutation - posterior rotation of sacrum relative to ilium, and/or anterior rotation of ilium relative to sacrum.
<ul>
 	<li>The pelvic floor muscles are examples of muscle that may counter-nutate the sacrum.</li>
</ul>
[caption id="attachment_126335" align="aligncenter" width="400"]<a href="https://brentbrookbush.com/wp-content/uploads/2018/10/Nutation.png"><img class=" wp-image-126335" src="https://brentbrookbush.com/wp-content/uploads/2018/10/Nutation.png" alt="Nutation and Counter-nutation of the Sacroiliac Joint" width="400" height="967" /></a> Nutation and Counter-nutation of the Sacroiliac Joint[/caption]

&nbsp;

Crossover (Study) Design - A type of longitudinal, repeated measures quasi-experimental design in which each group receives both treatments, but at different times. It is named "crossover" due to the patients "crossing-over" to the other treatment or sham group after a specified period of time.
<ul>
 	<li>This type of study has the advantage of every individual serving as their own control, which may reduce the influence of confounding variables.</li>
 	<li>Unfortunately, the design itself introduces the chances that anyone receiving the experimental variable in the first period will continue to be effected in the second period.</li>
</ul>
In a study by Senna et al., a cross-over design was used to investigate the difference load made on inter-set rest intervals (1).
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/strength-training-research-corner/heavy-vs-light-load-single-joint-exercise-performance-with-different-rest-periods/" target="_blank" rel="noopener">Senna, G.W., Rodrigues, B.M., Sandy, Scudese, Bianco, A, &amp; Dantas, E.H.M. (2017). Heavy vs light load single-joint exercise performance with different intervals. Journal of Human Kinetics, 58, 197-206. </a></li>
</ol>

Cross-sectional Study - a research design that involves gathering data from a population or representative subset at a specific point in time.
<ul>
 	<li>Example, the study by Karimi-Mobarake et al.(1) investigated the prevalence of genu varum and genu valgum among school children 7-11 years old in Iran.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/low-prevalence-of-genu-varum-and-valgum-among-elementary-school-children/" target="_blank" rel="noopener noreferrer">Karimi-Mobarake, M., Kashefipour, A., Yousfnejad, Z. The prevalence of genu varum and genu valgum in primary school children in Iran 2003-2004. (2005) Journal of Medical Science 5(1). 52-54</a></li>
</ol>

Cytokine - A broad and loose category of small proteins that act through receptors, and are especially important to immune function (inflammation).
<ul>
 	<li>Cytokines include substances such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells. Their definite distinction from hormones is a topic of continued research.</li>
</ul>
&nbsp;

Dependent variable - in research, this is the variable that is changed by the independent variable, most often this is the "outcome" of the study.
<ul>
 	<li>Example, in the study by Cleland et al. (1), the independent variable is "thoracic manipulation," and the dependent variable is "lower trapezius muscle strength."</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/short-term-effects-lower-thoracic-manipulation-lower-trapezius-muscle-strength/" target="_blank" rel="noopener noreferrer">Cleland J, Selleck B, Stowell T, Brown L, Alberini S, St. Cyr H, Caron T. Short-term Effects of Thoracic Manipulation on Lower Trapezius Muscle Strength.  Journal of Manual &amp; Manipulative Therapy. 2004; 12(2): 82-90</a></li>
</ol>

An anatomical direction; further from the trunk or center of the body

Example, the foot is at the distal end of the leg.

An arthrokinematic motion - a force applied to a body part that may result in the separation of joint surfaces, a reduction in intra-articular pressure, and/or an increase in intra-articlar space.

For example, to hang from one's hands (i.g. in preparation for a pull-up) results in a traction force on the glenohumeral joint (shoulder).

An anatomical term of location; back or upper surface

Example, shoe laces may compress tissues on the dorsal surface of the foot

The "drawing-in" maneuver is a common cue used during exercise and rehabilitation programs. A light contraction of the <a href="https://brentbrookbush.com/articles/muscular-anatomy/transverse-abdominis/" target="_blank" rel="noopener">transverse abominis</a> (and potentially the entire <a href="https://brentbrookbush.com/articles/corrective-exercise-articles/core-subsystems/intrinsic-stabilization-subsystem/" target="_blank" rel="noopener">intrinsic stabilization subsystem</a>) achieved by gently pulling the lower abdominal region away from one's waist band. This should have minimal effect on breathing, and should not be confused with a maximal contraction of the <a href="https://brentbrookbush.com/articles/muscular-anatomy/transverse-abdominis/" target="_blank" rel="noopener">transverse abdominis</a> resulting in a "vacuum pose".
<ul>
 	<li>Research often refers to this maneuver as the "abdominal drawing-in maneuver"; abbreviated ADIM.</li>
</ul>
Development and introduction of this cue into practice is based on the pivotal research and resulting text:
<ol>
 	<li>Carolyn Richardson, Paul Hodges, Julie Hides. Therapeutic Exercise for Lumbo Pelvic Stabilization – A Motor Control Approach for the Treatment and Prevention of Low Back Pain: 2nd Edition (c) Elsevier Limited, 2004</li>
</ol>

Faulty or abnormal movement; an alteration of normal kinematics.

For example, joint stiffness or a reduction in arthrokinematics motion that results in limited osteokinematic range of motion - inadequate inferior glide of the femoral head resulting in limited abduction of the hip.

The seeping into, or abnormal collection of fluid in a body cavity.

For example, knee effusion describes swelling within the knee joint.

Note: the word "effusion" is used differently in medicine than it is used in reference to the movement (seeping out) of liquids and gases, for example in chemistry.

&nbsp;

A trait of body tissues that allows a tissue to return to its resting length or state after deformation or stretch.
Example:  Muscle is elastic tissue; many muscles will return to their resting length after being stretched to 150% of that length without any appreciable change in tissue quality.

Elasticity: Elasticity refers to the ability of a cell to return to its resting length after being stretched/lengthened.
<ul>
 	<li>Note: this term is often confused with extensibility. Elasticity is not the ability to stretch; it is the ability to return to normal length after being stretched. Muscle tissue, connective tissue and even nerve tissue have varying levels of elasticity.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Epithelial cell - One of the four basic cell types, found lining the body's cavities, blood vessels, organs and constitutes most gland tissue.  These cells are specialized to aid with absorption, secretion, or act as a barrier from foreign objects.
<ol>
 	<li>Saladin, K. S., &amp; Miller, L. (1998). Anatomy &amp; physiology. New York (NY): WCB/McGraw-Hill.</li>
</ol>

Equilibrium - a state in which opposing forces or influences are balanced.
<ul>
 	<li>For example, to maintain a neutral trunk while pushing or pulling a weight in one hand, your core musculature must balance the force by creating an equal amount of force in the opposite direction.</li>
</ul>

The study of causation, or origination. The word is commonly used in the medical professions, where it may refer to the study of why things occur, or the reason behind why things act a certain way.

For example, the etiology of low back pain is a complex subject, with multiple contributing factors and various structures implicated.

<div class="gs_citr" tabindex="0">Evidence-based medicine (practice) is the integration of best research evidence with clinical expertise and patient(client) values (2)."</div>
<ul>
 	<li class="gs_citr" tabindex="0">...the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients (clients).  It involves the integration of at least (a) clinical expertise/expert opinion, (b) external scientific evidence, and (c) client/patient/caregiver perspectives to provide high-quality services reflecting the interests, values, needs, and choices of the individuals we serve (1).</li>
</ul>
&nbsp;
<ol>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Sackett, D. L., Rosenberg, W. M., Gray, J. M., Haynes, R. B., &amp; Richardson, W. S. (1996). Evidence based medicine: what it is and what it isn't. Bmj, 312(7023), 71-72.</li>
 	<li class="gs_citr" tabindex="0">Sackett D et al. Evidence-Based Medicine: How to Practice and Teach EBM, 2nd edition. Churchill Livingstone, Edinburgh, 2000, p.1</li>
</ol>

Excitability: The ability of a cell to change in membrane conductance as a response to stimulation.

<ul>
 	<li>For example, muscle cells are specialized to react to a change in membrane potential with contraction, where as nerve cells are specialized to propagate a change in membrane potential along there axons and communicate that message to other tissues via neurotransmitters.
</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Excitation threshold: The level that a depolarization must reach for an action potential to occur.
<ul>
 	<li>The excitation threshold is a contributing factor to the "all-or-none" response of muscle and nerves cells to a stimulus.</li>
</ul>

Exercise Progression - Modification of an exercise with the intent of promoting adaptation by increasing demand. This can be accomplished by increasing reps, load, tempo, range of motion, complexity, and/or challenge to an individual's stability.
<ul>
 	<li>Because load, reps, tempo and complexity are often explicitly noted, the term "exercise progression" is most often used throughout Brookbush Institute (BI) content to refer to an exercise, or series of exercises that make it harder to maintain stability with good form.
<ul>
 	<li>Sample Exercise Progression: <a href="https://brentbrookbush.com/vimeo_videos/kneeling-chop-pattern/" target="_blank" rel="noopener">Kneeling Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/static-standing-chop-pattern/" target="_blank" rel="noopener">Standing Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/single-leg-chop-pattern/" target="_blank" rel="noopener">Single-leg Chop</a></li>
</ul>
</li>
</ul>

Exercise regression - The opposite of progression; that is, modification of an exercise with the intent of reducing demand. This can be accomplished by decreasing reps, load, tempo, range of motion, complexity, and/or challenge to an individual's stability. Generally, regressions are used to modify an exercise to the client's current level of ability, with the intent of improving form, motor learning and retention.
<ul>
 	<li>Because load, reps, tempo and complexity are often explicitly noted, the term "exercise regression" is most often used throughout Brookbush Institute (BI) content to refer to an exercise or series of exercises that make it easier to maintain stability with good form.
<ul>
 	<li>Sample Exercise Regression: <a href="https://brentbrookbush.com/vimeo_videos/single-leg-chop-pattern/" target="_blank" rel="noopener">Single-leg Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/static-standing-chop-pattern/" target="_blank" rel="noopener">Standing Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/kneeling-chop-pattern/" target="_blank" rel="noopener">Kneeling Chop</a></li>
</ul>
</li>
</ul>

Experimental Research - Studies in which the researchers introduce the variable to be studied, with the intent of observing the outcome. This is different than observational research which observes the effect of a variable already present. Many texts also assert that experimental research should include randomization and ideally a control group, as is seen in Randomized Control Trials. Studies in which the variable is introduced by the researchers, but participants are not randomized may be considered Quasi-experimental research.
<ul>
 	<li>In this study by Esformes, the experimental variable was squat depth and the outcome measures observed were various performance measures related to power (1).</li>
</ul>
<ol>
 	<li><a href="https://brookbushinstitute.com/article/back-squat-depth-lower-body-post-activation-potentiation/" target="_blank" rel="noopener">Esformes, J., &amp; Bampouras, T. (2013). Effect of back squat depth on lower-body postactivation potentiation. Journal of Strength and Conditioning Research, 27(11), 2997-3000.</a></li>
</ol>
&nbsp;

Extensibility: The ability of a cell to be stretched or lengthened without damage (1).
<ul>
 	<li>For example, most cells would rupture with even a modest stretch, but muscles can stretch up to 3 times their contracted length.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

False Negative - the proportion of negatives in a group that were assessed incorrectly (assessed as negative when the patient was actually positive)
<ul>
 	<li>Test Results: Although most tests/assessments result in either a positive or negative, the accuracy of a test is dependent on the number  of positives and negatives that are correct. Therefore, when the accuracy of a test is determined, their are 4 possible results, because a positive or negative result could be right (true) or wrong (false).</li>
</ul>

False Positive - the proportion of positives in a group that were assessed incorrectly (assessed as positive when the patient was actually negative)
<ul>
 	<li>Test Results: Although most tests/assessments result in either a positive or negative, the accuracy of a test is dependent on the number  of positives and negatives that are correct. Therefore, when the accuracy of a test is determined, their are 4 possible results, because a positive or negative result could be right (true) or wrong (false).</li>
</ul>

The function of fascia is to transmit force, provide support, and protect tissues. Fascia can effect motion by:
Transmitting force from one or more muscles (example: the thoracolumbar fascia)
Restricting motion in cases of adaptive shortening and/or adhesion to proximal structures (example: iliotibial band in cases of lower-leg dysfunction)
Elastic recoil after stretching can contribute to force production (example: plyometric exercise)

Note: There is evidence that fascia may house more receptors related to human movement than other tissues. In this way fascia may act as a motherboard for the nervous system

The fascial system does not contract or develop trigger points, and its capacity to adapt to stretching and or strengthening exercise is limited, especially when compared to the adaptive capacity of muscle tissue.

Fibromyalgia - A loosely defined diagnosis that is associated with a combination of widespread pain in combination with 2) tenderness at 11 or more of the 18 specific tender point sites. Consideration may also be given to the presence of psychosocial stressors and inflammatory disease in the patients history. Newer research suggests that fibromyalgia may be at least in part due to central sensitization of myofascial pain, often associated with trigger points (1 - 4).
<ol>
 	<li>Wolfe, F. (2018). Fibromyalgia Syndrome and Fibromyalgia Syndrome Criteria: Problems in Definition and Validity. Fibromyalgia Syndrome and Widespread Pain: From Construction to Relevant Recognition.</li>
 	<li>Wolfe, F., Smythe, H. A., Yunus, M. B., Bennett, R. M., Bombardier, C., Goldenberg, D. L., ... &amp; Fam, A. G. (1990). The American College of Rheumatology 1990 criteria for the classification of fibromyalgia. Arthritis &amp; Rheumatism: Official Journal of the American College of Rheumatology, 33(2), 160-172.</li>
 	<li>Alonso-Blanco, C., Fernandez-de-las-Penas, C., Morales-Cabezas, M., Zarco-Moreno, P., Ge, H. Y., &amp; Florez-García, M. (2011). Multiple active myofascial trigger points reproduce the overall spontaneous pain pattern in women with fibromyalgia and are related to widespread mechanical hypersensitivity. The Clinical journal of pain, 27(5), 405-413.</li>
 	<li>Staud, R., Nagel, S., Robinson, M. E., &amp; Price, D. D. (2009). Enhanced central pain processing of fibromyalgia patients is maintained by muscle afferent input: a randomized, double-blind, placebo-controlled study. PAIN®, 145(1-2), 96-104.</li>
</ol>
&nbsp;

Muscles that act to reduce or prevent movement at proximal joints to improve force transmission.
Example: The muscles of the core are important fixators; reducing motion of the spine/trunk to enhance force transmission between the extremities and environment.

An increase in joint stability via compressive forces resulting from muscular contraction and increased tension in fascial structures (1,2).
<ul>
 	<li>This term is most often used in reference to core intrinsic stabilizers, the thoracolumbar fascia and the sacroiliac joint; however, force closure and form closure have been mentioned in the literature referring to other joints.</li>
 	<li>Related term: Form closure</li>
</ul>
<ol>
 	<li>Andry Vleeming, Vert Mooney, Rob Stoeckart. Movement, Stability &amp; Lumbopelvic Pain: <a class="glossaryLink " title="Glossary: Integration" href="https://brentbrookbush.com/glossary/integration/" target="_blank" rel="noopener noreferrer" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Integration&lt;/div&gt;&lt;div class=glossaryItemBody&gt;Making a whole of parts.&lt;br /&gt;&lt;br /&gt;Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.&lt;/div&gt;">Integration</a> of Research and Therapy. (c) 2007 Elsevier Limited</li>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., &amp; Snijders, C. J. (1995). The Posterior Layer of the Thoracolumbar Fascia| Its Function in Load Transfer From Spine to Legs. Spine, 20(7), 753-758.</li>
</ol>

The relative contribution of joint shape and structure to the stability of a joint (1,2).
<ul>
 	<li>This term is most often used in reference to the "rough" articulating surfaces of the sacroiliac joint and the wedge shape of the sacrum; however, force closure and form closure have been mentioned in the literature referring to other joints.</li>
 	<li>Related term: Force closure</li>
</ul>
<ol>
 	<li>Andry Vleeming, Vert Mooney, Rob Stoeckart. Movement, Stability &amp; Lumbopelvic Pain: <a class="glossaryLink " title="Glossary: Integration" href="https://brentbrookbush.com/glossary/integration/" target="_blank" rel="noopener noreferrer" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Integration&lt;/div&gt;&lt;div class=glossaryItemBody&gt;Making a whole of parts.&lt;br /&gt;&lt;br /&gt;Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.&lt;/div&gt;">Integration</a> of Research and Therapy. (c) 2007 Elsevier Limited</li>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., &amp; Snijders, C. J. (1995). The Posterior Layer of the Thoracolumbar Fascia| Its Function in Load Transfer From Spine to Legs. Spine, 20(7), 753-758.</li>
</ol>

An arthrokinematic motion - linear motion across a joint surface parallel to the plane of the adjacent joint surface, just as your posterior moves relative to a "slide" in a park.

For example, the glide of facet joint in the spine during spinal flexion and extension, or the posterior glide of the humeral head that must accompany anterior roll to maintain congruence with glenoid fossa during shoulder horizontal adduction.

A plane joint (also called an arthrodial joint, gliding joint or plane articulation) is a synovial joint which allows only gliding movement in the plane of the articular surfaces. The opposed surfaces of the bones are flat or almost flat, with movement generally limited by tight capsules and ligaments. Plane joints are numerous, are most often small, and allow very little motion.  Examples include the carpal joints of the wrist, the tarsal joints of the ankle, and the facet joints of the spine.

"...refers to the measurement of angles, in particular the measurement of angles created at human joints by the bones of the body (1).

&nbsp;
<ol>
 	<li>Cynthia C. Norkin, D. Joyce White. Measurement of Joint Motion: A Guide to Goniometry 3rd Edition. Copyright (C) 2003 by F.A. Davis Company</li>
</ol>

Ground reaction force (GRF) - The force exerted by the ground on the body in contact with it.

For example, when a runner's foot strikes the ground with a force equal to the mass of the individual times their acceleration due to gravity, momentum and muscular exertion, the ground exerts an equal and opposite force on the runner's foot.
<ul>
 	<li>GRF is often measured in research studies using force plates as a means of quantitatively measuring the force generated by an individual.</li>
</ul>

H-Band - Refers to the central zone of a sarcomere that looks lighter under a microscope.  This area of the sarcomere is a lighter portion of the A-band where there is no overlap between the thinner filaments (actin), and the thicker filaments (myosin).
<ul>
 	<li>Example, when a muscle contracts, actin and myosin cross-bridging occurs in the region of the A-band until the H-band is reached where no overlap occurs.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

A hinge joint (also called a ginglymus) is a synovial joint in which the articular surfaces fit one another in a way that only permits motion in one plane. Examples include the elbow, the knee (unless considered a condyloid joint) and the interphalangeal joints.

Holism (holistic) (biological holism) - (from Greek holos "all, whole, entire") is the idea that systems and their properties should be viewed as wholes, not just as a collection of parts.
<ul>
 	<li>Summarized by Aristotle in his "Metaphysics": "The whole is more than the sum of its parts". However, the term "holism" was introduced into language by the South African statesman Jan Smuts as recently as 1926. (Smuts J. C. 1987 [1926]. Holism and evolution. Cape Town: N &amp; S Press.)</li>
</ul>
Example: The Brookbush Institute promotes a holistic approach to human movement science, in which the muscular, fascial, articular and neural systems are not viewed as separable and all proximal segments are considered.

Hormone: Chemical messengers produced by the endocrine system, transported via tissue fluids such as blood, to stimulate cells to "act."
<ul>
 	<li>Example: Growth hormone is secreted by the pituitary gland in the brain; stimulating growth, cell reproduction and cell regeneration in certain types of cells</li>
</ul>
The English physician E. H. Starling discovered in collaboration with the physiologist W. M. Bayliss secretin, the first hormone, in 1902. (1).
<ol>
 	<li>Henriksen, J. H., &amp; de Muckadell, O. S. (2000). Secretin, its discovery, and the introduction of the hormone concept. Scandinavian journal of clinical and laboratory investigation, 60(6), 463-472.</li>
</ol>

A range of motion achieved by the patient/client that is more than normal.
<ul>
 	<li>Note: Both hyper-mobility and hypo-mobility may adversely affect motion and may lead to deleterious effects on joints and soft tissue over time. There is no evidence to suggest that more or less flexibility than normal is beneficial.</li>
</ul>
Example: If an individual can place their forehead on their knees they are likely hypermobile at one, if not several joints

Example 2: 110° of shoulder external rotation would be considered hyper-mobile.

Hyperplasia is an increase in organic tissue size due to an adaptive increase in the number of cells per organ.
<ul>
 	<li>Although muscle hyperplasia has been noted in some animals, human muscle tissue does not seem to have this adaptive ability.</li>
</ul>

A condition of excessive tone of the skeletal muscles; increased resistance of muscle to passive stretching.  May be related to increased neural drive, synergistic dominance, trigger points, reflexive over-activity, and/or muscle length.
Example:  Individuals who exhibit ankle eversion and abduction during an overhead squat assessment likely have hypertonic fibularis (peroneal) muscles.

Muscular hypertrophy is an increase in muscle mass/size due to increase in the volume and cross-sectional area (CSA) of individual muscle cells. The increase in cross-sectional area can be attributed to an an increase in contractile proteins and structural elements (myofibrillar hypertophy), as well as an increase in glycogen storage and elements related to metabolism (sarcoplasmic hypertophy). Hypertrophy is an adaptation of both cardiac and skeletal muscle fibers in response to progressive increases in workload.
<ul>
 	<li>Note: Hypertrophy is not hyperplasia. Hyperplasia is an increase in muscle size due to an adaptive increase in the number of muscle fibers/cells per muscle. This type of adaptation does not occur in human muscle tissue.</li>
</ul>

A range of motion achieved by a patient/client that is less than normal.
<ul>
 	<li>Note: Both hyper-mobility and hypo-mobility may adversely affect motion and may lead to deleterious effects on joints and soft tissue over time. There is no evidence to suggest that more or less flexibility than normal is beneficial.</li>
</ul>
Example: If the end range of shoulder external rotation is reached and measured as 75° during goniometric assessment, the client/patient is exhibiting hypomobility of the glenohumeral joint (shoulder).

Hypothesis - a proposed explanation for a phenomenon; "scientific hypotheses" are generally constructed in a way that is testable or falsifiable.
<ul>
 	<li>Example: The hypothesis, "excessive knee valgus may be correlated with future knee pain and injury," has been the subject of several studies published over the last decade.</li>
</ul>

Diminished tone of skeletal muscles; diminished resistance of muscles to passive stretching.   May be related to inhibition, reciprocal inhibition, arthrokinematics inhibition and/or  increased resting length of muscle.
Example:  If your knees cave (hip adduction) during a squat or leg-press it is likely that your gluteus medius is hypotonic.

I-Band - Refers to the part of the muscle cell that looks lighter under a microscope.  This area of the cell is lighter due to parallel arrangement of thinner filaments (actin), and no overlap with the thicker filaments (myosin).
<ul>
 	<li>As a muscle contracts, the I-bands will decrease in width and move closer to one another.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Independent variable - in research, this is the variable or phenomenon being manipulated in the study.
<ul>
 	<li>Example, in the study by Ghanbari et al. (1), the independent variable is "knee joint mobilization", the dependent variable is "quadriceps muscle strength."</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/effect-knee-joint-mobilization-quadriceps-muscle-strength/" target="_blank" rel="noopener noreferrer">Ghanbari A. and Kamalgharibi S. (2013). Effect of knee joint mobilization on quadriceps muscle strength. International Journal of Health and Rehabilitation Sciences. 2(4): 186-191</a></li>
</ol>

An anatomical direction; toward the bottom (below)

Example, the mouth is inferior to the eyes

A reduction in neural drive, muscular activity, and or force output due to altered neuromuscular reflex.  Alterations in neuromuscular reflex may occur due to increases in muscle length (hypothesis: increased excitation threshold), altered reciprocal inhibition in response to increased antagonist tone, and or alterations in joint motion (arthrokinematics inhibition).

Making a whole of parts.

Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.

Intermuscular Coordination - Optimal timing and motor unit recruitment of agonists, antagonists, synergists, neutralizers, stabilizers and fixators.

Example: Role of Muscles during Hip Extension
<ul>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Prime Mover" href="https://brentbrookbush.com/glossary/prime-mover/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Prime Mover&lt;/div&gt;The muscle most responsible for a joint action under load -&lt;br /&gt;&lt;br /&gt;That is, the muscle that can produce the most force for a given joint action. Often this term is used synonymously with the term agonist. The prime mover as defined above, may or may not be the most active muscle for a joint action during activities of daily living.&lt;br /&gt;&lt;br /&gt;Example: the gluteus maximus is the most powerful hip extensor and therefore the prime mover; however, the hamstrings are likely the most active hip extensors during low level activities like walking or standing.">Prime Mover</a>:  <a href="https://player.vimeo.com/external/82855344.hd.mp4?s=54c3e7d98fb9d4e0af8d282c85ba9b3e">Gluteus maximus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Synergists" href="https://brentbrookbush.com/glossary/synergists/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Synergists&lt;/div&gt;Muscles that assist the prime mover in performing a joint action.&lt;br /&gt;&lt;br /&gt;That is, all muscles that can perform a joint action that are not the prime mover, are termed synergists.&lt;br /&gt;Example: The rectus abdominis is the prime mover of spinal flexion. All other muscles that can perform spinal flexion are synergists including – external obliques, internal obliques and psoas.">Synergists</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/biceps-femoris/">Biceps femoris (long head)</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/semitendinosus-and-semimembranosus/">semitendinosus, semimembranosus</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/adductors/">posterior head of adductor magnus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Antagonist" href="https://brentbrookbush.com/glossary/antagonists/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Antagonist&lt;/div&gt;Muscles that oppose the prime mover and synergists for a given joint action.&lt;br /&gt;&lt;br /&gt;That is, all the muscles that can perform the opposing joint action.&lt;br /&gt;&lt;br /&gt;Example: The triceps and anconeus are antagonists during elbow flexion.">Antagonists</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/psoas/">Psoas</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/iliacus/">iliacus</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/tensor-fascia-latae-tfl/">tensor fascia latae</a> (TFL),<a href="https://brentbrookbush.com/articles/muscular-anatomy/rectus-femoris/"> rectus femoris</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/adductors/">anterior adductors (especially pectineus)</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/sartorius/">sartorius</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Neutralizer" href="https://brentbrookbush.com/glossary/neutralizers/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Neutralizer&lt;/div&gt;Muscles that oppose unwanted joint motions created by the prime mover and/or synergists, and/or muscles that prevent unwanted ancillary motion.&lt;br /&gt;Example: The teres minor and infraspinatus neutralize the internal rotation force created by the pectoralis major during horizontal adduction of the shoulder.">Neutralizers</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-minimus/">Gluteus minimus</a> and <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-medius/">anterior fibers of gluteus medius</a> neutralize external rotation force of <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-maximus/">gluteus maximus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Stabilizer" href="https://brentbrookbush.com/glossary/stabilizers/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Stabilizer&lt;/div&gt;Muscles whose primary role is to improve arthrokinematics by maintaining optimal alignment of joint surfaces.&lt;br /&gt;&lt;br /&gt;Most often these muscles are the most intrinsic muscles of a joint, have a larger percentage of Type I muscle fibers and are rich in proprioceptors.&lt;br /&gt;Example: The muscles of the rotator cuff act as stabilizers for most shoulder motions.">Stabilizers</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/deep-rotators-of-the-hip/">Deep rotators of hip</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Fixator" href="https://brentbrookbush.com/glossary/fixators/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Fixator&lt;/div&gt;Muscles that act to reduce or prevent movement at proximal joints to improve force transmission.&lt;br /&gt;Example: The muscles of the core are important fixators; reducing motion of the spine/trunk to enhance force transmission between the extremities and environment.">Fixators</a>: <a href="https://brentbrookbush.com/articles/core-subsystems/intrinsic-stabilization-subsystem/">Intrinsic stabilization subsystem</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/rectus-abdominis/">rectus abdominis</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/internal-obliques/">internal</a> and <a href="https://brentbrookbush.com/articles/muscular-anatomy/external-obliques/">external obliques</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/quadratus-lumborum/">quadratus lumborum</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/erector-spinae/">erector spinae</a></li>
</ul>
&nbsp;

Example from: <a href="https://brentbrookbush.com/articles/anatomy-articles/introduction-to-functional-anatomy/kinesiology-of-the-hip/" target="_blank" rel="noopener">Introduction to Functional Anatomy: Kinesiology of the Hip</a>

Intramuscular coordination refers to the coordinated recruitment of motor units within a single muscle. This concept is used to explain increases in maximal strength and power; however, the coordinated and sequential recruitment of motor units is also essential to strength endurance and smooth coordinated motion.  Related terminology may include; motor unit recruitment, preferential recruitment, rate coding, sequence, etc..

Example: It is hypothesized that the "shaking" noted during a novice exercisers attempt at an activity like the <a href="https://brentbrookbush.com/vimeo_videos/ball-crunch-and-progressions/" target="_blank">stability ball crunch</a> may be due to relatively poor intramuscular coordination. Rather than smooth, sequential firing of rectus abdominis motor units, groups of motor units turn on and off in an uncoordinated manner.

Pertaining to the same side

Example, the quadratus lumborum performs ipsilateral flexion; lateral flexion toward the same side as the muscle.

An isoform, or variant, is a member of a set of similar proteins, that originate from the same gene, or gene family.
<ul>
 	<li>Example, the variations in myosin heavy chain proteins (MHC I, MHC IIA, MHC IIB/X) that contribute to the characteristic differences between muscle fiber types.</li>
</ul>

“The Prime Assumption”
Everything crossing a joint will influence joint motion during every joint action.

A concept that has expanded over the past several decades to describe the integration of 4 body systems (muscle, joints, fascia and nerves), as well as, the coordinated function of various body segments (e.g. hip, knee and ankle) to produce motion. Kinetic referring to motion, and chain being an analogy for the interdependent link between systems.

Example, the posterior kinetic chain, refers to the integrated function of nerves, muscles, fascia and joints on the posterior side of the body.

The concept of the kinetic chain was originally adapted from the work of a mechanical engineer named Franz Reuleaux (Kinematics of Machinery (1875)) by Dr. Arthur Steindler in 1955 (Steindler A: Kinesiology of the Human Body. Springfield, IL, Charles C. Thomas Co.. 1955).

Latent Trigger Point - A myofascial trigger point that is not painful at rest, only painful when palpated, and may or may not exhibit a characteristic referral pain pattern when palpated.  Latent trigger points do result in an acute point of sensitivity, in a taut band of muscle, and may restrict range of motion (1).

Note: Based on the clinical experience, the Brookbush Institute suggests that latent trigger points (sometimes refereed to as Tender Points) are more common than active trigger points. Further, they are likely addressed more often than trigger points; being the intended target of many soft-tissue mobility techniques.
<ol>
 	<li>David G. Simons, Janet Travell, Lois S. Simons, Travell &amp; Simmons’ Myofascial Pain and Dysfunction, The Trigger Point Manual, Volume 1. Upper Half of Body: Second Edition,© 1999 Williams and Wilkens</li>
</ol>

An anatomical direction; further from the midline

Example, the anterior deltoid is lateral to the pectoralis major

Length/Tension Relationship - The amount of force generated by a muscle is dependent on sarcomere length.
<ul>
 	<li>The ability of sarcomere to maximally produce force occurs when sarcomere length results in optimal overlap between actin and myosin. Stretching a sarcomere decreases overlap between actin and myosin filaments and reduces force production (1-3). When length is less than optimal, actin from opposite ends overlap and interfere with cross-bridging, and myosin filament are compressed as they contact the the Z-disk also reducing force (4)</li>
</ul>
<ol>
 	<li>Gordon, A. M., Huxley, A. F., &amp; Julian, F. J. (1966). The variation in isometric tension with sarcomere length in vertebrate muscle fibres. The Journal of physiology, 184(1), 170-192.</li>
 	<li>Edman, K. A. P. (1966). The relation between sarcomere length and active tension in isolated semitendinosus fibres of the frog. The Journal of Physiology, 183(2), 407-417.</li>
 	<li>Lieber, R. L., Loren, G. J., &amp; Friden, J. (1994). In vivo measurement of human wrist extensor muscle sarcomere length changes. Journal of neurophysiology, 71(3), 874-881.</li>
 	<li>Lieber, R. L. (2002). Skeletal muscle structure, function, and plasticity. Lippincott Williams &amp; Wilkins.</li>
</ol>
&nbsp;

Levels of Evidence - Relative to evidence-based practice, levels of evidence are an attempt to describe the strength of the results measured in a clinical trial or research study.  Note: levels of evidence do not supersede the critical evaluation of an experienced professional, and should be viewed as guidelines - a meta-analysis may be poorly constructed (Level IA), and a comparative study (Level III) may employ new technologies and a strong methodology.


The Levels of Evidence used by the Brookbush Institute, as described by Shekelle et al.(1):
<ul>
 	<li class="p1">IA - Evidence from meta-analysis of randomized controlled trials</li>
 	<li class="p1">IB - Evidence from at least one randomized controlled trial</li>
 	<li class="p1">IIA - Evidence from at least one controlled study without randomization</li>
 	<li class="p1">IIB - Evidence from at least one other type of quasi-experimental study</li>
 	<li class="p1">III - Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies</li>
 	<li class="p1">IV - Evidence from expert committee reports or opinions or clinical experience of respected authorities, or both</li>
</ul>
<ol>
 	<li>Shekelle, P. G., Woolf, S. H., Eccles, M., &amp; Grimshaw, J. (1999). Developing clinical guidelines. Western Journal of Medicine, 170(6), 348.</li>
</ol>

Likelihood Ratios - Likilihood ratios are used for assessing the value of performing a diagnostic test. They use sensitivity and specificity to determine whether a test result usefully changes the practitioner's chance (probability) of reaching the correct assessment. Calculation of likelihood ratios is based on Baye's theorem.
<ul>
 	<li>Positive Likelihood Ratio (LR+) - The ratio of a positive test result in people with the pathology to a positive test result in people without the pathology.</li>
 	<li>Negative Likelihood Ratio (LR-) - The ratio of a negative test result in people with the pathology to a negative test result in people without the pathology.</li>
</ul>

Longitudinal Study - a research design that involves observing the same variables, several times over a period of time.
<ul>
 	<li>Example, the study by Hewett et al. (1) is a type of longitudinal study called a "cohort study." This study investigated whether excessive knee valgus during landing was a predictor of knee injury risk in adolescent females over the course of a season.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/research-review-increased-valgus-during-landing-predicts-acl-injury-in-adolescent-female-athletes/" target="_blank" rel="noopener noreferrer">Hewett, T. E., Myer, G. D., Ford, K. R., Heidt, R. S., Colosimo, A. J., McLean, S. G., &amp; Succop, P. (2005). Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes A prospective study. The American journal of sports medicine, 33(4), 492-501</a></li>
</ol>

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