The Brookbush Institute Glossary
A list of terms and definitions used in our courses and articles.
A
A-band
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 the overlap of myosin and actin proteins and is where these proteins interact.
Abdominal Drawing-In Maneuver (ADIM)
The "drawing-in" maneuver is a common cue used during exercise and rehabilitation programs. A light contraction of the transverse abdominis (and potentially the entire intrinsic stabilization subsystem) achieved by gently pulling the lower abdominal region away from one's waistband. This should have minimal effect on breathing, and should not be confused with a maximal contraction of the transverse abdominis resulting in a "vacuum pose". Abdominal drawing-in maneuver (ADIM) is a cue used in exercise and rehabilitation programs to activate the transverse abdominis and intrinsic stabilization subsystem.
Abduction
Abduction: A frontal plane joint action that results in movement away from the midline of the body.
Accuracy
Accuracy is a measure of how well a test identifies true positives and true negatives. It is calculated as the proportion of individuals correctly identified by the test results.
Action Potential
An "action potential" is a rapid temporary change in the electrical charge of a cell membrane when the stimulus threshold is reached. This is an "all-or-none" process.
Activation Technique
Activation exercises are single-joint movements designed to target specific under-active muscles while minimizing the contribution of over-active synergists. These exercises aim to address muscle imbalances that can lead to postural dysfunction, and cannot be multi-joint movements due to compensation patterns. For example, the side-lying leg raise exercise is a gluteus medius activation involving resisted hip abduction with specific cues to minimize TFL contribution. Activation exercises can be beneficial for injury prevention, improving muscle activation, and enhancing performance. Some synonyms for activation exercises include isolation exercises, muscle activation techniques, and corrective exercises.
Active Stretching
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. This technique helps improve flexibility, range of motion, and athletic performance.
Active Structure
An active structure is any tissue crossing a joint that is actively contracting (exhibits an increase in activity). By definition, only muscle tissue can be "active structures". The active structures involved in maintaining arthrokinematic motion include all of the muscles crossing the joint, especially the antagonists and proximal stabilizing muscles.
Adduction
Adduction: A frontal plane joint action that results in movement toward the midline of the body.
Adenosine Triphophatase (ATPase)
Adenosine triphosphatase (ATPase) is an enzyme that catalyzes the breakdown of adenosine triphosphate (ATP) to adenosine diphosphate (ADP), releasing energy for various processes like muscular contraction. This dephosphorylation reaction is crucial for the proper functioning of cells and organisms.
Adenosine Triphosphate (ATP)
ATP is a molecule that provides energy for muscular contraction and human movement. It is composed of an adenine group, a ribose group, and three molecules of inorganic phosphates. Hydrolysis of ATP results in the cleaving of a phosphate group, releasing energy. Adenosine diphosphate and an inorganic phosphate group are also produced.
Agonist (Muscle)
Agonists: Muscles that perform a joint action, including the prime mover and synergists. That is, unlike the terms prime mover and synergist, agonist refers to all of the muscles that can perform a joint action.
Algometery
Algometry, also known as dolorimetery, is a technique used to measure the amount of pressure that results in sensitivity or pain, typically through the use of an algometer. The procedure is commonly used in trigger point research to establish a minimum pain pressure threshold (PPT), where a lower PPT indicates greater sensitivity and pain, while a higher PPT indicates less sensitivity and pain. PPT is a critical outcome measure in pain research, allowing practitioners to understand the extent of a patient's pain and monitor changes in pain threshold over time.
All-or-none Principle (Law)
The all-or-none principle is a fundamental concept in physiology. It states that a nerve or muscle cell's response to a stimulus is independent of the strength of the strength. It is all or none.
Amortization Phase
The amortization phase is the brief transition period between the eccentric (muscle lengthening) and concentric (muscle shortening) phases of a stretch-shortening cycle (SSC) during high-velocity (power) movements.
Anatomical Directions
Anatomical directions are terms used to describe a location on the body. Note that all anatomical directions are paired; that is, each has an opposite. We have counted 15 anatomical directions commonly used in reference to human anatomy.
Anatomical Position
Anatomical Position: This is a specific anatomical reference position that refers to the body in a standing position, with the head and eyes forward, arms at sides with palms forward, and feet together and parallel.
Antagonists (Muscle)
Antagonists: Muscles that oppose the agonists (including the prime mover and synergists) for a given joint action. That is, all of the muscles that can perform the opposing joint action.
Anterior
Anterior is an anatomical direction that refers to the front of the body. For example, the face is on the anterior aspect of the head. Synonyms for anterior include front, rostral, or ventral. The opposite of anterior is "posterior."
Anterior Tipping (Scapula)
Anterior Tipping (Scapula): A sagittal plane joint action of the scapula (shoulder blade) where the superior portion of the scapula tilts forward over the top of the rib cage.
appendicular bone
Explore the fascinating structure of the appendicular skeleton, comprising approximately 126 bones including the arms, legs, pelvis, clavicle, and scapula. Distinguished from the 'axial skeleton', it plays a crucial role in our movement and physical coordination. Learn about its origins from the term 'appendage', denoting a constituent part.
Appendicular Skeleton
The appendicular skeleton is composed of the bones of the arms, legs, and supporting bones such as the pelvis, clavicle, and scapula. It is distinct from the axial skeleton and comprises approximately 126 bones.
Arthrogenic Inhibition
Athrogenic inhibition is a neuromuscular reflex that reduces the activity of muscles crossing a joint exhibiting signs of dysfunction following injury, surgery, or inflammation.
Arthrokinematic Motion (Arthrokinematics)
Arthrokinematic Motion: Small amplitude motions between bone surfaces at a joint. The arthrokinematic motions include roll, glide (slide or translation), spin, compression, and distraction (traction). Arthrokinematic motions accompany osteokinematic motions to maintain joint congruence.
Assessment
Assessment is the act of evaluating a patient's health or motion and determining its importance, size, or value. Assessments compare results to normative data or an ideal model to determine if an aspect of health or motion is contributing to the patient's symptoms or movement impairment. Types of assessments include those to clear a patient for intervention, highlight contraindications, or refine exercise/intervention selection. Examples include special tests in orthopedic medicine and goniometry. Synonyms for assessment include evaluation and testing. Related terms include diagnosis, treatment, and rehabilitation.
Autogenic Inhibition
Autogenic inhibition is a neuromuscular reflex that results in a reduction in muscle activity following an excessive or sustained increase in tension and stimulation of Golgi tendon organs (GTO).
Axial Skeleton
The axial skeleton is composed of bones in the head, neck, trunk, and spinal column. It does not include the pelvis.
B
Balance
Balance is the ability to maintain the body's center of mass over its base of support. Balance can be static or dynamic. Maintaining balance is harder on a single leg because the center of mass must stay over a much smaller base of support.
Ball-and-socket Joint
A ball-and-socket joint is a synovial joint in which the rounded or spherical end of one bone fits into a cup-like depression of another bone. Examples include the shoulder and hip.
Base of Support
Discover the importance of Base of Support (BoS) in stability, balance, sports, and rehabilitation. Learn how BoS impacts performance and fall prevention.
Bilateral
Bilateral refers to the "both sides." Bilateral is a term used to describe movements or structures that occur on both sides of the body.
Biopsychosocial (BPS) Model
The Biopsychosocial (BPS) Model is a more comprehensive approach to understanding health and illness by integrating biological, psychological, and social factors.
C
Case Control Study
A case-control study is a particular form of a 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.
Caudal
Caudal: An anatomical direction that refers to "toward the tail," relative to the human body, this term refers to toward the tailbone (sacrum and coccyx).
Cavitation
Cavitation is the formation of an empty space within a solid body or fluid. Cavitation sounds result from the separation of joint surfaces, which results in a rapid decrease in intra-articular pressure (cavitation), which results in degassing of synovial fluid (mostly carbon dioxide), the creation of a cavitation bubble within the joint, and the sound itself is either the result of bubble collapse or bubble formation/tribonucleation.
Center Of Mass
The center of mass is an object's mean position of mass; that is, a point that is perfectly surrounded by an equal amount of mass in all directions. The center of gravity (CoG) is the 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. For 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 back squat, the CoM would be anterior to the naval.
Cephalad
Cephalad is an anatomical direction that refers to movement towards the head. It is often used in medical terminology to describe the location of body parts or the direction of movement. Synonyms for cephalad include cranial, superior, and rostral. Related terms include caudad, inferior, and posterior.
Circuit Training
Circuit Training (a.k.a. vertical loading): When the first set of each exercise is performed sequentially (commonly, with little rest between exercises), and then the next set of each exercise is performed.
Cohort Study
A cohort study is a research design that follows a group of individuals who share a common characteristic or experience over a period of time. This longitudinal study design is frequently used in medicine and epidemiology to investigate the etiology or cause-and-effect relationship between exposure to a specific factor and the occurrence of an outcome. The independent variable in a cohort study is exposure, while the dependent variable is the outcome of interest. One example of a cohort study is the investigation of trunk muscle response time to off-loading in Yale Varsity Athletes by Cholewicki et al. (2005). Understanding cohort studies is crucial for researchers who want to identify risk factors and determine the efficacy of interventions.
Comparable Sign
A comparable sign is a combination of pain, stiffness, and/or spasm during an examination that is comparable to the patient's symptoms. One common error made during evaluation with special tests is the 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 for every individual. Basing your assessment on positive tests that resulted in "concordant/comparable signs" will improve your chances of arriving at the correct diagnosis.
Compensation Pattern
Compensation patterns are alternative movement patterns that the human body adopts to work around dysfunction or impairment in the movement system. A common example of compensation is functional knee valgus, where a lack of calf extensibility leads to inward bowing of the knees during a squat.
component motions
Dive into the intricate world of arthrokinematic motion, characterized by small amplitude motions between bone surfaces at a joint. Comprising roll, glide, spin, compression, and distraction, these motions accompany osteokinematic motions for maintaining joint congruence. For instance, the talus exhibits a posterior glide on the tibia during ankle dorsiflexion.
Compression
Compression is an arthrokinematic motion. ompression is an arthrokinematic motion. The approximation of two surfaces; that is, a force that reduces the space or increases the pressure between two surfaces. Similar to the way the teeth are "clenched" together during a bite. An anatomical example would include forces that direct one bone surface into another resulting in a reduction in intra-articular volume.
Concave
Concave (Concavity): A shape is concave if at least part of it curves inward. That is, the outline or surface is curved like the interior surface of a bowl, or the entrance of a "cave."
Concentric Contraction
Concentric Muscle Contraction: A type of muscle contraction in which activation of motor units and the production of force results in joint motion and the shortening of the muscle.
Concordant Sign
A concordant sign refers to the patient's specific pain, symptom, or complaint that is related to their condition. During evaluation with special tests, it is important to identify the pain or discomfort that is comparable to the patient's complaint. Positive tests that result in concordant signs will improve the chances of arriving at the correct diagnosis.
Conductivity
Conductivity refers to the ability of cells to transmit electrical impulses. In anatomy and physiology, conductivity plays a crucial role in the functioning of muscles and nerves. 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 sarcomere.
Condyloid Joint
A condyloid joint is an ovoid articular surface received into an elliptical cavity. These joints permit movement in two planes, for example, the radiocarpal joint of the wrist.
Connective Tissue
Connective tissue cells are one of the four basic cell types. Their primary roles are supporting, protecting, transmitting force, and exchanging nutrients with other cells in the body.
Contractility
Contractility is the unique ability of muscle cells to shorten when stimulated. This is largely due to the highly organized and unique arrangement of myofilaments (actin and myosin) within the muscle cells.
Contralateral
Contralateral refers to the "opposite side." Contralateral is a term used to describe movements or structures that occur on the opposite side of the body.
Convex
Convex (Convexity): A shape is convex if at least part of it curves outward, like the external surface of a sphere. Think of "ex" in "convex" as meaning "out" or "outside."
Convex-Concave Rule (and concave-convex rule)
Convex-concave rule and concave-convex rules describe an arthrokinematic pattern that minimizes the inherent migration of the center of the axis of rotation of a joint, in the direction of arthrokinematic roll. Note, these rules were developed with the intent to aid in teaching, specifically to assist with “visualizing” joint motion. They were not intended to dictate the direction of joint mobilization or manipulation techniques (although they can aid in decision-making).
Core Subsystems (Slings)
Vleeming et al. proposed that specific groups of thoracolumbar fascial layers, muscles, and ligaments function synergistically: the posterior oblique sling, the anterior oblique sling, and the longitudinal sling.
Corrective Exercise
Corrective exercisers are self-administered exercises that are recommended with the intent to address an assessed movement impairment and improve the quality of motion. Corrective exercise may also be referred to as therapeutic exercise and/or rehabilitation exercise (or specific exercise when compared to general strengthening). Corrective exercise is commonly included in corrective exercise programs, movement preparation warm-ups, home exercise programs (self-management programs), and supervised physical rehabilitation programs
Correlational Research
Correlational research is non-experimental research method in which the statistical relationship between two variables is investigated. In 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). 1. 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
Counter Nutation
Counter-nutation is the posterior rotation of the sacrum relative to the ilium, and/or anterior rotation of the ilium relative to the sacrum. The pelvic floor muscles are examples of muscles that may counter-nutate the sacrum.
Counter-movement Jump (CMJ)
The Counter-movement Jump (CMJ) is a vertical jump performed with a preparatory downward movement prior to take-off (the "counter-movement"). It begins with a quick eccentric/pre-stretch phase (rapid squat-like descent and arm backswing), followed by a brief amortization phase (transition), and ends with a forceful concentric phase (upward jump).
Cranial
Cranial: An anatomical direction that refers to "toward the head", that is toward the cranium (the bones of the head).
Cross Sectional Study
A cross-sectional study is a research design used to gather data from a population or representative subset at a specific point in time. It involves collecting information on a particular phenomenon of interest, such as prevalence or incidence, and exploring its relationship with other factors. This type of study is often used to examine the distribution of health-related behaviors, conditions, or outcomes in a population. A good example of a cross-sectional study is the research conducted by Karimi-Mobarake et al. to investigate the prevalence of genu varum and genu valgum in school children in Iran. Other synonyms for cross-sectional study include prevalence study, snapshot study, and observational study. Related terms to cross-sectional study include longitudinal study, retrospective study, and prospective study.
Crossover Design
Crossover design is a quasi-experimental design used in longitudinal, repeated measures studies. In this design, each group receives both treatments at different times. This study design has the advantage of every individual serving as their own control, which may reduce the influence of confounding variables. However, the design itself introduces the chances that anyone receiving the experimental variable in the first period will continue to be affected in the second period.
Cytokine
Cytokines are small proteins that play a crucial role in immune function, particularly in inflammation. They include interferon, interleukin, and growth factors, secreted by immune cells to affect other cells. Cytokines are still being researched to distinguish them from hormones.
D
Daily Undulating Periodization
Daily Undulating Periodization (DUP) is a type of periodization training in which training intensity changes from session to session within a week. Unlike block periodization, in which intensity remains relatively consistent for weeks, DUP typically varies day to day, while still allowing for progressive overload over time.
Delayed Onset Muscle Soreness (DOMS)
Delayed Onset Muscle Soreness (DOMS): The soreness felt in muscles following exercise. Often with little to no soreness experienced immediately following exercise, peak values 1 - 3 days post-exercise, and complete recovery 3 - 7 days post-exercise. The delay in the experience of peak soreness is not completely understood, but it is likely the result of the time course of the inflammatory response resulting from the inherent muscle tissue damage caused by intense exercise.
Dependent Variable
In research, the dependent variable is changed by the independent variable, most often this is the "outcome" of the study. For example, in the study by Cleland et al. (1), the independent variable is "thoracic manipulation," and the dependent variable is "lower trapezius muscle strength." 1. 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 & Manipulative Therapy. 2004; 12(2): 82-90
Depression (Scapula)
Scapular Elevation: This joint action of the scapula (shoulder blades) is movement downwards along the ribcage, towards the buttocks.
Distal
Distal: An anatomical direction that refers to a location or structure that is further from the center of the body. The opposite of distal is proximal.
Distraction
Distraction (traction): Distraction is an arthrokinematic motion. A force applied that separates two surfaces; that is, a force that increases the space or decreases the pressure between two surfaces. Similar to the way a suction cup is pulled from a window. An anatomical example would include forces that pull one bone surface apart from another, increasing intra-articular volume.
Dorsal
Dorsal: An anatomical direction that refers to the back or upper surface of the body. In humans, this term is almost exclusively used in reference to the dorsum of the foot and hands (top surface), or in reference to the back of the central nervous system. For example, shoe laces may compress tissues on the dorsal surface of the foot.
Dorsiflexion
Dorsiflexion: A sagittal plane joint action of the ankle that results in a decrease in the angle between the dorsal (top) surface of the foot and the tibia.
Downward Rotation (Scapula)
Scapular Upward Rotation: A joint action of the scapula (shoulder blades) where the inferior angle moves down and in, causing the glenoid fossa (shoulder socket) to tilt downward.
Drop Set
Drop Sets: Performing a set with reps-to-failure, followed by an immediate reduction in load and a continuation of (without rest) reps-to-failure; repeat until volitional fatigue.
Dysfunction
Dysfunction: An abnormality or impairment. A deviation from optimal. For example, Lower Extremity Dysfunction (LED) is a model of the common lower extremity movement impairments and/or deviations from normal alignment during motion.
Dyskinesis
Dyskinesis is faulty or abnormal movement; an alteration of normal kinematics. This condition can lead to a reduction in arthrokinematic motion and limited osteokinematic range of motion, such as inadequate inferior glide of the femoral head resulting in limited abduction of the hip. Dyskinesis can be caused by a variety of factors, including neurological disorders, musculoskeletal injuries, and even medications. Synonyms for dyskinetic include abnormal movement, atypical motion, and faulty kinematics.
E
Eccentric Contraction
Eccentric Muscle Contraction: A type of muscle contraction in which, despite activation of motor units and the production of force, the external resistance forces the muscle to lengthen.
Effusion
Effusion 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.
Elasticity
Elasticity is the ability of a cell to return to its resting length after being stretched or lengthened. It is often confused with extensibility, which is the ability to stretch. Muscle tissue, connective tissue, and nerve tissue have varying levels of elasticity.
Elevation (Scapula)
Scapular Elevation: This joint action of the scapula (shoulder blades) is movement upwards along the ribcage, towards the ears.
Endomysium
The endomysium is a thin layer of areolar (loose) connective tissue that surrounds each muscle cell (myocyte).
Epimysium
The epimysium is a dense, fibrous layer of connective tissue that surrounds the entire muscle, acting as the outermost protective sheath for the muscle itself.
Epithelial Cell
Epithelial cells, also called epithelium, are 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 absorption and secretion or act as a barrier from foreign objects.
Equilibrium
Equilibrium is a state of balance where opposing forces or influences are equal. It is essential in maintaining proper posture and balance during physical activities. For instance, when lifting weights, your core muscles must create an equal amount of force in the opposite direction to maintain a neutral trunk.
Etiology
Etiology is 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. Understanding causation is crucial in developing effective treatment plans and preventative measures. Synonyms for causation include causality, origin, and reason. Related glossary terms include correlation, risk factor, and pathophysiology.
Eversion
Eversion: A frontal plane movement of the ankle in which the sole of the foot rotates outward, away from the body's midline.
Evidence Based Practice
Evidence-based practice involves the integration of the best scientific research evidence, clinical expertise, and patient/client values in decision-making.
Excitability
Excitability is the ability of a muscle cell to change in membrane conductance as a response to stimulation. For example, muscle cells are specialized to react to a change in membrane potential with contraction, whereas nerve cells are specialized to propagate a change in membrane potential along their axons and communicate that message to other tissues via neurotransmitters. 1. Saladin, K. (2012). Anatomy & Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.
Excitation Threshold
The excitation threshold is the minimum level of depolarization required for an action potential to occur in nerve and muscle cells. It plays a crucial role in the all-or-none response of these cells to a stimulus.
Excitation-Contraction Coupling
Excitation-Contraction (E-C) Coupling refers to the steps in a process of muscular contraction from action potential (excitation) to the power stroke (contraction).
Exercise Progression
Exercise progression refers to increasing the demand of an exercise to promote adaptation.
Exercise Regression
Exercise regression refers to decreasing the demand of an exercise to reduce stress. Generally, regressions are used to decrease the demand on tissues, improve the rate of recovery, or enhance learning by decreasing the gap between the individual's current level of ability and the challenge provided by the exercise.
Experimental Research
Experimental research design is a scientific approach in which researchers introduce a variable to study its effect on an outcome. Unlike observational research, which only observes the effect of a variable already present, experimental research aims to control the variables involved. It typically involves randomization and a control group to ensure unbiased results and can help establish cause-and-effect relationships between variables. Quasi-experimental research, on the other hand, lacks randomization and may have limited control over the variables. Some synonyms for experimental research design include randomized controlled trials, intervention studies, and laboratory experiments. Related glossary terms include independent variable, dependent variable, control group, and randomization.
Extensibility
Extensibility refers to the ability of a cell to be stretched or lengthened without damage. While most cells would rupture with even a modest stretch, muscles can stretch up to three times their contracted length without harm. This property is essential for the proper functioning of muscles and other tissues that need to stretch and contract regularly. Understanding extensibility is crucial for medical professionals and researchers studying the physiology of the human body.
Extension
Extension: A sagittal plane joint action that results in an increase in the angle between two bones.
External Rotation
External Rotation (Lateral Rotation): A rotational (spinning) movement in which the anterior side of a segment moves away from the midline of the body in the transverse plane.
F
False Negative
A false negative is a term used to describe the proportion of negatives in a group that were assessed incorrectly as negative when the patient was actually positive. 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, there are 4 possible results, because a positive or negative result could be right (true) or wrong (false).
False Positive
A false positive is a term used to describe the proportion of positives in a group that were assessed incorrectly (assessed as positive when the patient was actually negative). 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, there are 4 possible results, because a positive or negative result could be right (true) or wrong (false).
Fascial System
The fascial system consists of connective tissue. An example is the thoracolumbar fascia which is a sheet of connective tissue that spans from latissimus dorsi to gluteus maximus across the lumbar spine (see image). 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: throrocolumbar 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)
Femoral Anteversion
Femoral Anteversion: Forward (anterior) rotation of the femoral neck relative to the femoral condyles (the distal end of the femur) in the transverse plane.
Femoral Retroversion
Femoral Retroversion: Backward (posterior) rotation of the femoral neck relative to the femoral condyles (the distal end of the femur) in the transverse plane.
Fibromyalgia
Fibromyalgia is a condition characterized by widespread pain and tenderness at specific tender point sites. It may also involve psychosocial stressors and inflammation. Recent research suggests that it may be caused by central sensitization of myofascial pain, often associated with trigger points. This loosely defined diagnosis poses challenges in terms of definition and validity. Fibromyalgia is typically diagnosed using the 1990 American College of Rheumatology criteria. Treatment may involve a combination of medication, physical therapy, and lifestyle changes. Some synonyms for fibromyalgia include fibromyalgia syndrome and fibrositis. Related glossary terms include myofascial pain syndrome, trigger points, and chronic pain.
Fixators (Muscle)
Fixators are muscles that act to reduce or prevent movement of joints proximal to the joint in motion.
Flexion
Flexion: A sagittal plane joint action that results in a decrease in angle between two bones.
Force Closure
Force closure is a term used to describe the increase in joint stability via compressive forces resulting from muscular contraction and increased tension in fascial structures. This concept is often applied to the core intrinsic stabilizers, thoracolumbar fascia, and the sacroiliac joint. Forcing closure is an essential component of load transfer from the spine to the legs. For example, the stability of the sacroiliac joint is due to the muscle supporting it (force closure) and the shape of the sacrum and ilium (form closure). Related terms: load transfer, fascia, sacroiliac joint, stabilizers, lumbopelvic pain.
Force Velocity Curve
The force-velocity curve illustrates the inverse relationship between the force a muscle can generate and the velocity of joint movement. As movement velocity increases, the amount of force that a muscle can contribute to the motion decreases, and vice versa.
Form Closure
Form closure refers to the contribution of joint shape and structure to the stability of a joint, often observed in the sacroiliac joint and the sacrum. This term is closely related to force closure, which involves the use of muscles and ligaments to provide stability. Related glossary terms include force closure, joint stability, and load transfer.
Frontal Plane
Frontal Plane (Coronal Plane): The frontal plane divides the body into front and back halves and refers to motion that is side-to-side & up and down.
G
Glide
Glide is an arthrokinematic motion. A linear movement of an object across a surface parallel to the plane of that surface. Similar to the way skis slide down a snowy slope. An anatomical example would be the posterior glide of the humeral head during internal rotation of the humerus to maintain congruence with the glenoid fossa.
Gliding Joint
Gliding joints are also known as arthrodial or plane joints. These synovial joints enable limited gliding movements due to flat bone surfaces and tight joint capsules. Common examples include carpal joints in the wrist, tarsal joints in the ankle, and facet joints in the spine.
Goniometry
Goniometric assessments refer to the measurement of joint angles in the body, particularly those created by the bones at human joints. This process involves using a goniometer, a specialized device that measures the range of motion and flexibility of specific joints in the body. Goniometric assessments are often used in physical therapy and other movement analysis fields to help diagnose joint issues and track progress in treatment. Synonyms for goniometric assessments include joint angle measurements and range-of-motion testing. Related glossary terms may include goniometer, joint mobility, and joint axis.
Ground Reaction Force
Ground reaction force (GRF) is 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. It is an important concept in biomechanics and is often measured using force plates. GRF is influenced by factors such as body weight, speed, and surface type.
H
H-band
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 actin and myosin filaments.
Hinge Joint
A hinge joint (also called a ginglymus joint) is a type of synovial joint that permits motion in one plane, similar to the hinge of a door.
Holism
Holism, or biological holism, is the concept that systems and their properties should be viewed as complete entities, rather than just a collection of individual parts. For 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.
Horizontal Abduction
Horizontal Abduction (a.k.a. Horizontal Extension): A transverse plane joint action that results in movement away from the midline of the body.
Horizontal Adduction
Horizontal Adduction (a.k.a. Horizontal Flexion): A transverse plane joint action that results in movement toward the midline of the body.
Horizontal Loading
Horizontal Loading: Performing all sets for a given exercise before moving on to the next exercise.
Hormone
Hormones are chemical messengers produced by the endocrine system and transported via tissue fluids such as blood to stimulate cells to act. Growth hormone is an example of a hormone that is secreted by the pituitary gland in the brain, stimulating growth, cell reproduction, and cell regeneration in certain types of cells.
Hypermobility
Hypermobile joints refer to a range of motion that is greater than normal, which can have negative effects on the joints and soft tissues over time. This condition can be caused by a variety of factors, including genetic predisposition, connective tissue disorders, and certain medical conditions. While hypermobility may initially seem advantageous, it can lead to an increased risk of injury, chronic pain, and joint instability.
Hyperplasia
Hyperplasia is a medical condition where there is an increase in the number of cells in an organ or tissue, leading to an increase in size. While hypertrophy is an increase in the size of a cell. Although muscle hyperplasia has been noted in some animals, human muscle tissue does not seem to have this adaptive ability.
Hypertonic
Hypertonicity is a condition where the skeletal muscles have excessive tone, leading to increased resistance to passive stretching. This can be caused by various factors such as neural drive, synergistic dominance, trigger points, reflexive over-activity, and muscle length.
Hypertophy
Hypertrophy is the process of increasing muscle mass and size due to an increase in the volume and cross-sectional area of individual muscle cells. This adaptation occurs in response to progressive increases in workload and can be attributed to an increase in contractile proteins, glycogen storage, and elements related to metabolism. It is important to note that hypertrophy is not the same as hyperplasia, which is an increase in muscle size due to an adaptive increase in the number of muscle fibers/cells per muscle. Common types of muscular hypertrophy include myofibrillar hypertrophy and sarcoplasmic hypertrophy.
Hypomobility
Hypomobility is a condition in which a person experiences a limited range of motion in a joint. For example, if the end range of shoulder external rotation is reached and measured as 75° during a goniometric assessment, the client/patient is exhibiting hypomobility of the glenohumeral joint (shoulder). This can be caused by a variety of factors, such as injury, disease, or chronic inflammation. Symptoms of hypomobility can include stiffness, pain, and difficulty performing everyday activities
Hypothesis
A hypothesis is a proposed explanation for a phenomenon that is testable or falsifiable. In the scientific method, hypotheses are used to guide the design of experiments and to evaluate the results. For 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. Synonyms for the term hypothesis include conjecture, assumption, theory, and proposition. Related glossary terms include scientific method, null hypothesis, alternative hypothesis, and statistical significance.
Hypotonic
Hypotonicity of skeletal muscles refers to the diminished tone and resistance of muscles to passive stretching. This condition may be caused by inhibition, reciprocal inhibition, arthrokinematics inhibition, or increased resting length of muscle. If you experience knee cave (functional knee valgus) during a squat, jumping, or running, it is likely that your gluteus medius is hypotonic.
I
I-band
I-band: Refers to the part of the muscle cell that looks lighter under a microscope (near the z-disk). This area of the cell is lighter due to the parallel arrangement of actin with no overlap with the thicker myosin filaments.
Independent Variable
Independent variables are key components of research studies that are being manipulated to test their effects on dependent variables. In this context, independent variables are the phenomena or factors that researchers alter or change to observe their impact on the outcome of the study.
Inferior
Inferior: An anatomical direction that refers to a structure located "below" another structure. Generally, this term is used to describe the relative position of a structure when the body is in the anatomical position. For example, the chin is inferior to the mouth.
Integration
Integration is an approach to human movement emphasizes on looking at the body as a whole, rather than isolated parts. This approach allows for a better understanding of how the different parts of the body work together to produce movement. The Brookbush Institute, a leading provider of continuing education for health and fitness professionals, utilizes an integrative approach to explain and address human movement. Through this approach, students can learn how to assess movement patterns and design effective training programs. Synonyms for integrationist include holistic, comprehensive, and synergistic. Related terms include movement assessment, functional anatomy, and corrective exercise.
Intermuscular Coordination
Intermuscular coordination refers to the ability of agonists, antagonists, synergists, neutralizers, stabilizers, and fixators to work together in a coordinated manner to produce efficient and effective movement. This involves the optimal timing and motor unit recruitment of these muscles to produce smooth and coordinated movement patterns. Understanding intermuscular coordination is important for improving athletic performance, preventing injuries, and rehabilitating injuries.
Internal Rotation
Internal Rotation (Medial Rotation): A rotational (spinning) movement in which the anterior side of a segment moves toward the midline of the body in the transverse plane.
Intramuscular Coordination
Intramuscular coordination refers to the coordinated recruitment of motor units within a single muscle. This can explain increases in maximal strength and power, as well as strength endurance and smooth coordinated motion. Related terminology includes motor unit recruitment, preferential recruitment, rate coding, and sequence. Poor intramuscular coordination can lead to shaking during exercises like the stability ball crunch.
Inversion
Inversion: A frontal plane movement of the ankle in which the sole of the foot rotates inward, toward the body's midline.
Ipsilateral
"Ipsilateral" refers to the "same side." In anatomy and physiology, this term describes movements or structures that occur on the same side of the body.
Isoform
An isoform is a variant protein that originates from the same gene or gene family. For example, myosin heavy chain proteins (MHC I, MHC IIA, MHC IIB/X) contribute to the characteristic differences between muscle fiber types.
Isometric Contraction
Isometric Muscle Contraction: A type of muscle contraction in which activation of motor units and the production of force does not result in joint motion or a change in muscle length. This occurs when the force produced by the muscle is equal to the external resistance. Functionally, isometric contractions can be thought of as actions that stabilize or maintain the position of a joint or body segment in opposition to an external load.
J
Joint Action
Joint Action: Joint actions are the labels given to the movement of bones around a joint. Each pair of joint actions is associated with a plane of motion. For example, the joint actions flexion and extension are associated with the sagittal plane.
Joint Manipulation
A joint manipulation is a high-velocity force applied to a joint with the intent of increasing passive arthrokinematic range and/or achieving a therapeutic effect. Generally, manipulations are performed with a small amplitude thrust and may result in cavitation and audible "pop" (Note, manipulations are referred to as "Grade V Mobilizations" in some publications).
Joint Mobilization
Joint Mobilization is a passive force applied to a joint with the intent of increasing passive arthrokinematic range and/or achieving a therapeutic effect. Generally, mobilizations are performed with a slow, oscillatory motion (1 - 2 cycles per second).
K
Kinesiology
Kinesiology can literally be defined as "the study of human movement"; however, this term generally refers to the study of the biomechanical aspects of movement.
Kinetic Chain
The Kinetic Chain is a concept that describes the interdependent link between four body systems - muscles, joints, fascia, and nerves - and how they work together to produce motion. The coordinated function of various body segments, such as the hip, knee, and ankle, is also a crucial aspect of the Kinetic Chain. For example, the posterior Kinetic Chain refers to the integrated function of nerves, muscles, fascia, and joints on the backside of the body. This concept was adapted from the work of mechanical engineer Franz Reuleaux and introduced to kinesiology by Dr. Arthur Steindler in 1955.
L
Latent Trigger Point
A latent trigger point is a type of myofascial trigger point that is not painful at rest but only when palpated. It may or may not exhibit a characteristic referral pain pattern when palpated and can result in an acute point of sensitivity, taut band of muscle, and restricted range of motion. Latent trigger points are more common than active trigger points and are often the intended target of soft-tissue mobility techniques.
Lateral
Lateral: An anatomical direction that refers to a structure further from the midline of the body. For example, the anterior deltoid is lateral to the pectoralis major.
Lateral Flexion
Lateral Flexion: A frontal plane joint action of the spine that results in a decrease in the angle between two bones (e.g. bending to one side).
Length-Tension Relationship
Length-Tension Relationship: The amount of force a muscle generates depends on the length of its sarcomeres.
Levels Of Evidence
Levels of evidence provide a framework to describe the strength of results obtained from clinical trials or research studies. The Brookbush Institute, as described by Shekelle et al., identifies five levels of evidence: IA (evidence from meta-analysis of randomized controlled trials), IB (evidence from at least one randomized controlled trial), IIA (evidence from at least one controlled study without randomization), IIB (evidence from at least one other type of quasi-experimental study), and III (evidence from non-experimental descriptive studies). However, levels of evidence should not supersede the evaluation of an experienced professional and should be viewed as guidelines. Synonyms for levels of evidence include strength of evidence, quality of evidence, and hierarchy of evidence.
Likelihood Ratios
Likelihood 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. The calculation of likelihood ratios is based on Baye's theorem.
Linear Periodization
Linear periodization is a type of periodization training that progresses from high-volume, low-intensity training to low-volume, high-intensity training.
Longitudinal Study
A longitudinal study is a research design that involves observing the same variables repeatedly over an extended period. This type of study can provide insights into how variables change over time and their relationship with each other. For example, the Hewett et al. study investigated whether excessive knee valgus during landing predicted knee injury risk in adolescent females over a season. Longitudinal studies can be further classified as cohort, panel, or trend studies, depending on their focus. Cohort studies follow a specific group over time, while panel studies observe a fixed sample. Trend studies examine changes in a population over time. Other related terms include cross-sectional study, observational study, and prospective study.
M
M-line
M-line: It refers to a dark line through the middle of a sarcomere, bisecting the two halves between Z disks. This is not labeled in the image but is visible.
Maximum Voluntary Contraction (MVC)
Maximum voluntary contraction (MVC) is a standard measure of muscle strength that is commonly used for research. Maximum strength is defined as the highest voluntary force that can be achieved (maximum participant effort). To aid in standardization and reliability MVCs are most often determined on a machine (e.g. leg extension) during an isometric contraction, known as a maximum voluntary isometric contraction (MVIC).
Medial
Medial: An anatomical direction that refers to a structure nearer to the midline of the body. For example, the sternum is medial to the pectoralis major.
Mitochondria
Mitochondria are double membrane organelles that specialize in generating ATP via aerobic respiration. The density of mitochondria in a cell can indicate its activity level and dependence on aerobic respiration for its primary function.
Mobility
Mobility refers to the ability to move freely and easily and is a crucial aspect of physical function. Techniques like release, joint mobilization, stretching, and soft tissue mobilization can help increase mobility, which is typically measured as the range of motion at a joint. Hypermobility and hypomobility are also important concepts to understand in the context of mobility. Synonyms for mobility include movement, flexibility, and motility. Related glossary terms include range of motion, joint health, and physical therapy.
Model
Models are simplified representations used to explain the workings of complex systems. They are particularly useful for aiding in the understanding of common changes and pathologies within these systems. For example, the Lower Extremity Dysfunction (LED) model is designed to help understand changes in lower extremity motion resulting from or causing common lower extremity pathologies. Models can be created for a wide range of systems, including biological, mechanical, and social systems, and can be used to explore hypothetical scenarios and predict outcomes. Synonyms for models include simulations, frameworks, and conceptualizations.
Motor Unit
Motor Unit: A motor unit includes a motor nerve (nerve cell axon) and all of the muscle cells (fibers) it innervates.
Movement Impairment
Movement impairment is a measurable loss in function. For example, a patient presents with a complaint of shoulder pain and can no longer reach overhead, and during a goniometric assessment of shoulder flexion (with scapula motion) exhibits 150° of available range of motion (optimal 180°). The measurable loss of range of motion is a "movement impairment".
Muscle Cell (Myocyte)
Muscle cells, also known as myocytes, are specialized cells designed for contraction and force production.
Muscle Fiber Dysfunction
Muscle fiber dysfunction is a neuromyofascial phenomenon that results from excessive stress on a muscle fiber. It is characterized by increased tone, taut bands, palpable nodules, myalgia, and centralization. The causes of muscle fiber dysfunction include excessive stress, insufficient blood flow, metabolic crisis, muscle fiber changes, chemical changes, and nervous system adaptation.
Muscle Length Test
Muscle length tests (MLT) tests assess range of motion by elongating muscles and measuring resistance to passive lengthening. Common tests include the Latissimus Dorsi Length Test, Hamstring Length Test, Thomas' Test, and Gastrocnemius/Soleus Length Test. Muscle length tests are also referred to as muscle flexibility tests.
Muscular System
The muscular system produces force and moves the skeletal system. All muscles play a role in joint actions, acting in multiple planes to accelerate, stabilize, and decelerate movement. Synergistic muscle groups work together for ease of analysis. Learn more about the function of the muscular system.
Myalgia
Myalgia is a medical term that refers to muscle pain. It can be caused by various factors such as injury, overuse, infection, or certain medical conditions. Symptoms of myalgia include muscle soreness, stiffness, and weakness. Treatment options include rest, pain relievers, physical therapy, and addressing the underlying cause.
Myofascial Pain Sydrome (MPS)
Myofascial Pain Syndrome (MPS) is a pain syndrome characterized by tenderness at points in firm bands of skeletal muscle, specific patterns of pain referral associated with each point, frequent emotional, postural, and behavioral contributing factors and, frequently associated symptoms and concomitant diagnoses. Based on the Brookbush Institute's review of "Muscle Fiber Dysfunction and Trigger Points" it would seem that MPS encompasses all of the observable signs and symptoms associated with muscle fiber dysfunction, that are not fibromyalgia.
Myofascial Slings
Myofascial Sling: A functional network of muscles, fascia, and connective tissues that together transmit force, stabilize joints, and coordinate multi-joint movements.
Myoglobin
Myoglobin is a protein-based pigment found in muscle cells that aids hemoglobin in delivering oxygen to support aerobic metabolism. This pigmented protein has a high affinity for oxygen, and its concentration in muscle cells determines the cells' ability to fuel aerobic metabolism. Type I muscle fibers, like in the soleus muscle, have a higher concentration of myoglobin and a better ability to carry and deliver oxygen to the cells. Myoglobin is crucial for athletes and individuals engaging in physical activities as it helps increase endurance and reduce fatigue. Understanding myoglobin and its role in muscle cells can help individuals maximize their aerobic performance and maintain a healthy body.
N
Nerve Cell
Nerve cells, also known as neurons, are specialized cells in the nerve tissue that can detect stimuli, respond quickly, and transmit coded information to other cells. They form the basic unit of the nervous system and work together to carry out complex functions such as movement, sensation, and cognition. Glial cells provide support and protection to neurons. The sciatic nerve, for example, is a bundle of axons from neurons whose bodies are close to the spinal cord. Synonyms include neuron, afferent neuron, sensory cells, and sensory neuron.
Nervous System
The functions of the nervous system are sensory input, integration, control of muscles and glands, and mental activity.The function of the nervous system is control. The nervous system maybe seperated into the central nervous system (CNS) and peripheral nervous system. The central nervous system (CNS) includes the brain and spinal cord and can be thought of as the "thinking", organizing, or regulating center The peripheral nervous system (PNS) includes the nerve cells and axons that communicate information from sensory receptors via afferent (into) nerves, and efferent (away from) nerves that communicate information to organs, muscles, glands, etc… to effect their function.
Neuromuscular Efficiency
Neuromuscular efficiency is the ability of the neuromuscular system to allow agonists, antagonists, stabilizers, neutralizers, and fixators to work together to produce, reduce, and dynamically stabilize the entire kinetic chain in all three planes. This is crucial for optimal movement and injury prevention in sports and everyday activities.
Neuromuscular Inhibition
Neuromuscular Inhibition: A reduction in tone, neural drive, muscle activity, muscle recruitment, and/or force output due to altered neuromuscular reflex and an increase in inhibitory signals (increased excitation threshold of alpha-motor neurons).
Neuromuscular Junction
The neuromuscular junction is the functional connection between the synapse of a motor nerve and the motor end plate of a muscle cell. For example, for an action potential to successfully initiate contraction, the action potential must result in the release of neurotransmitters across the neuromuscular junction. Saladin, K. (2012). Anatomy & Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.
Neutralizers
During a joint action, neutralizers are muscles that oppose the unwanted or ancillary joint motions that result from the force generated by the prime mover and/or synergists.
Nociceptive Motor Control Alterations
Nociceptive Motor Control Alterations (Pain-Adaptive Motor Control Changes): A term describing pain-induced modifications in muscle activity, encompassing both nociceptive muscle inhibition and nociceptive muscle facilitation.
Non-linear Periodization
Non-linear periodization is a type of periodization training in which intensity does not progress in a single direction. Instead of following a sequential pattern (e.g., from low to high intensity), non-linear periodization varies intensity levels throughout a training cycle, often targeting specific adaptations (e.g., hypertrophy, power, endurance, maximum strength), without adhering to a linear progression of loads or intensity.
Normative Data
Normative data is typically obtained from a large, randomly selected representative sample from the wider population. It is data from a reference population that establishes a baseline distribution for a score or measurement, and against which the score or measurement can be compared. For example, the "ideal" range of motion for a goniometric assessment of a joint is established using normative data collected from various research studies. This data can be used to compare an individual's score or measurement to the average performance of others in the same group.
Nutation
Nutation is the anterior rotation of the sacrum relative to the ilium and/or the posterior rotation of the ilium relative to the sacrum. The erector spinae and psoas muscles are examples of muscles that may nutate the sacrum.
O
Observational Study
Observational studies are used in scientific research to draw inferences from a population or sample where the independent variable cannot be controlled due to ethical concerns or logistical constraints. This type of research is commonly used in fields such as epidemiology, psychology, and sociology, where it is often impossible or unethical to manipulate variables. For example, the Souza et al. study (1) is observational because knee pain cannot be randomly assigned. This study compared individuals with knee pain to "matched-controls" without knee pain.
Optimal Alignment
Optimal Alignment: A mean range of segment (bone, joint, muscle, nerve) alignment that is absent of signs correlated with dysfunction, pain, or an increased risk of injury. Additionally, alignment recommendations may be influenced by optimal length-tension relationships, biomechanical advantage, or force generation capacity.
Organelle
Organelles are any structure within a cell that carries out one of its metabolic roles. For example, mitochondria, nucleus, endoplasmic reticulum, and the cell wall are all examples of organelles. Synonyms for organelles include cell organelles, subcellular organelles, and cell components. Related glossary terms include cell membrane, cytoplasm, and cell nucleus.
Osteokinematic Motion
Osteokinematic motion: The movement of bones around a joint, commonly referred to as joint actions (e.g., flexion, internal rotation, abduction, etc.). Osteokinematic motions are distinct from arthrokinematic motions (e.g., spin, glide, roll, etc.).
P
Pain Neuroscience Education (PNE)
Pain Neuroscience Education (PNE) is an approach that emerged in the early 2000s that aims to improve patient outcomes by improving a patient's understanding of pain.
Pain Science
Pain Science refers to the multidisciplinary study of the complex processes that contribute to the pain experience, including the influence of sensory, cognitive, emotional, and social factors.
Passive Structure
A passive structure is any tissue crossing a joint that is not actively contracting. For example, The passive structures involved in maintaining arthrokinematic motion include the joint capsule and ligaments and the tonicity of muscles not actively involved in the joint motion. For example, during shoulder abduction, excessive superior glide is opposed by portions of the joint capsule, the inferior glenohumeral ligament, and the inherent tone (resistance to stretch) of the latissimus dorsi and teres major.
Perimysium
The perimysium is a layer of dense, irregular connective tissue that surrounds groups of muscle fibers (myocytes) to form bundles known as fascicles.
Periodization Training
Periodization refers to the planned manipulation of acute training variables, such as load, sets per muscle group, repetition tempo, exercise selection, etc., to optimize adaptation, improve performance, and prevent overtraining.
physiological movements
Get a grasp of osteokinematic motion, the movement of bones around a joint, often described by terms such as flexion, extension, abduction, adduction, and rotation. It involves the relative movement of the bone shafts. For instance, flexion and extension depict the osteokinematic motion of the elbow. Range of Motion (ROM) generally refers to this type of motion.
Pigment Biology
Pigment is an organic compound that gives color to plant or animal tissue. Examples of pigments include chlorophyll in plants, hemoglobin in blood, and myoglobin in muscle tissue. Pigments play important roles in photosynthesis, vision, and camouflage.
Pivot Joint
Pivot joints are a type of synovial joint that allows for rotational motion. Examples include the articulation between C1 and C2, and the proximal radioulnar joint.
Planes of Motion
Planes of motion are imaginary two-dimensional surfaces that divide the body relative to directions of motion (forward, sideways, rotation, etc.): sagittal plane, frontal plane (coronal plane), and transverse plane (horizontal plane).
Plantar
Plantar: An anatomical direction that refers to the bottom or lower surface of the body. In human anatomy, this term is almost exclusively used to refer to structures on the bottom of the foot. For example, plantar fasciitis is a diagnosis of inflation of the fascia on the bottom side of the foot.
Plantar Flexion
Plantar flexion: A sagittal plane joint action of the ankle that results in the foot pointing away from the body or downward.
Plyometric
Plyometric exercises are high-velocity movements designed to increase power by utilizing the stretch-shortening cycle (SSC). These exercises are characterized by a rapid eccentric (muscle lengthening) phase, a brief amortization (isometric transition) phase, and an explosive concentric (muscle shortening) phase.
Post Activation Potentiation
Post-activation potentiation (PAP) is a phenomenon in which a muscle's force is acutely increased as a result of its contractile history. Learn how to optimize inter-set rest periods, total reps, load, and volume to improve your performance in exercises like box jumps and back squats.
Posterior
Posterior is an anatomical direction that refers to the back of the body. For example, the gluteus maximus is on the posterior side of the pelvis and hip. Synonyms for posterior include dorsal, back, and rear. The opposite of posterior is "anterior."
Posterior Tipping (Scapula)
Posterior Tipping (Scapula): A sagittal plane joint action of the scapula (shoulder blade) where the superior portion of the scapula tilts backward, and the inferior angle moves forward.
Posture
Posture is arthro- and osteo-kinematic alignment maintained by myofascial activity and length, as a result of sensation, integration, and activation by the nervous system - both statically and dynamically. Good posture is essential for optimal health and well-being, as it helps to reduce the risk of injury, improve breathing and circulation, and enhance physical performance.
Power
Power is defined as the rate at which work is performed. In health and human performance, the term "power" refers to an individual's ability to generate force rapidly.
Predictive Values
Predictive values in diagnostic testing, are the proportion of true positives and true negatives. The positive predictive value (PPV) and negative predictive value (NPV) describe the accuracy of a diagnostic test; however, unlike sensitivity and specificity, predictive values are largely dependent on the prevalence of the dysfunction in the examined population.
Prime Mover (Muscle)
Prime Mover: The muscle that can produce the most force for a joint action. Generally, this is the muscle that will generate the most force during a joint action when exerting force against an external load.
Prone
Prone: An anatomical position that refers to face down, palm(s) down, or lying on one's stomach. For example, when performing the exercise "planks" the person is face down in a prone position.
Prospective Study
A prospective study is a longitudinal study that follows a group of individuals over time (into the future) to determine how a set of predetermined factors effects, or is correlated with certain outcome measures. These studies are important for determining the cause of various orthopedic pathologies because in most cases potentially harmful variables cannot be experimentally introduced to determine if they will result in injury. Unfortunately, these studies are notoriously expensive, are vulnerable to participant attrition, and may not easily detect rare diseases or injuries.
Protraction
Scapular Protraction (Scapular Abduction): A joint action of the scapula (shoulder blades), that is movement away from the spine and towards the front of the body.
Proximal
Proximal is an anatomical direction that refers to a location or structure that is closer to the center of the body. "In close proximity to the center of the body."
Pyramid Sets
Pyramid Sets: Increasing or decreasing load with each set. This includes ascending pyramids, descending pyramids, bell-shaped pyramids, U-shaped pyramids, etc.
R
Randomized Control Trial
Randomized Controlled Trials (RCTs) are an essential tool for evaluating the effectiveness of new medical treatments, interventions, and procedures. In an RCT, participants are randomly assigned to an experimental group receiving the treatment being tested, or a control group receiving a placebo or sham intervention. By randomly assigning participants to groups, RCTs reduce the risk of bias and confounding variables, providing more accurate data to evaluate the effectiveness of the intervention.
Range of Motion (ROM)
Range of Motion (ROM) is the amount a bone can move around a joint. ROM can be measured in degrees with goniometry.
Rate Coding
Rate coding, also known as frequency coding, is a model of neuronal communication that describes how the intensity of a stimulus affects the rate of action potentials. This glossary term explains the all-or-none principle and how additional information is coded in the frequency of action potentials. Rate coding was first shown by ED Adrian and Y Zotterman in 1926.
Rate of Force Development
Rate of Force Development (RFD) refers to the speed at which force increases during a muscular contraction. Mathematically, this is expressed as the change in force divided by the change in time.
Rate of Perceived Exertion (RPE)
The rate of perceived exertion (RPE) is a scale used to assign a number to a participant’s perceived level of exertion. The scale is a subjective and qualitative (as opposed to objective and quantitative) measure; however, several studies have demonstrated validity, sensitivity, and reliability
Reciprocal Inhibition
Reciprocal Inhibition: A neuromuscular reflex that may result in a decrease in the activity of the functional antagonist when agonist activity increases.
Recovery Time
Recovery is the time to return to pre-exercise (pre-intervention), pre-intervention, or pre-injury values. Generally, this is measured in days but may be measured in minutes, hours, or weeks.
Reductionist
Reductionistic practices involve oversimplifying complex ideas or issues to the point of obscuring or distorting them. Reductionism can be harmful as it fails to account for the complexity of issues, leading to incorrect assumptions and conclusions. For instance, grouping self-administered techniques with diverse intents into a single category can obscure the differences between them and lead to wrong conclusions. It is essential to recognize the limitations of reductionism and instead embrace a more holistic approach to understanding complex phenomena.
Referred Trigger Point Pain
Referred (Trigger Point) Pain occurs when pain is generated by a trigger point, but is felt in a pattern that includes an area distal to that point. This type of pain is usually not congruent with the distribution of a peripheral nerve or dermatomal segment, and can often be reproduced by stimulation of the original trigger point. For example, trigger points associated with cervical spine muscles may refer to pain to the head's front, top, or side, contributing to tension-type and cervicogenic headaches.
Refractory Period
Refractory period refers to the time immediately following an action potential when the neuron is unable to generate another action potential. This is a critical process that ensures the proper functioning of the nervous system.
Regional Interdependence
Regional interdependence is the concept that a patient’s primary musculoskeletal symptom(s) may be directly or indirectly related or influenced by impairments from various body regions and systems regardless of proximity to the primary symptom(s). For example, thoracic manipulation having a positive effect on a patient's complaints associated with shoulder impingement syndrome is an example of regional interdependence.
Relative Flexibility
When one muscle group or joint is stiff, it can cause compensatory movement in adjoining joints that are controlled by muscles and soft tissues that exhibit less stiffness. This is known as relative flexibility and can lead to movement impairment syndromes. For example, a reduction in hip extension range of motion may increase lumbar extension during gait.
Release Technique
Release Technique (in Manual Therapy and Corrective Exercise): Release techniques are a group of interventions that generally intend to improve mobility by decreasing tone, tension, density, or activity. These techniques most often include pressure, position, vibration, mobilization, manipulation, or needling of soft tissue.
Relevance
Relevance is a crucial aspect of assessment that pertains to the appropriateness and connection of the evaluation method to the client's condition. In medical settings, choosing the right assessment tool is critical for accurate diagnosis and treatment planning. For instance, dorsiflexion goniometry may not be relevant for assessing a client/patient with Upper Body Dysfunction (UBD). Understanding relevance in assessment requires careful consideration of the client's unique circumstances and needs. Failure to assess relevance can lead to incorrect diagnoses, ineffective treatment plans, and potential harm to the patient. Synonyms for relevance include pertinence, applicability, and importance. Related glossary terms include validity, reliability, and sensitivity.
Reliability
Reliability refers to the ability of a test or assessment to produce consistently accurate results, time after time, regardless of who is performing the assessment. If an assessment cannot produce consistent results, then a professional cannot determine the accuracy of a measurement, compare that measurement to normative data, or reassess and compare measurements taken on two separate dates. The concept behind reliability is fairly simple and falls into two broad categories. Intra-tester reliability - assesses the agreement (or lack of) between test scores from one test administration to the next (administered by a single tester). Inter-tester reliability - assesses the agreement (or lack of) between two or more testers in their assessment.
Reps in Reserve (RIR)
Reps-in-Reserve (RIR) is a training strategy intended to approximate effort while performing fewer reps than sets to failure. The number of RIR is an exerciser's estimate of how many more reps they could have performed before reaching failure.
Responsiveness
Responsiveness is the ability of a muscle cell to respond or react to stimuli (1). For example, a muscle cell may respond to chemicals/hormones in the bloodstream by increasing intra-cellular production of certain proteins. 1. Saladin, K. (2012). Anatomy & Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.
Retraction
Scapular Retraction (Scapular Adduction): A joint action of the scapula (shoulder blade) that is movement toward the spine and the back of the body.
Retrospective
A retrospective study is a type of longitudinal study that analyzes past data to examine suspected factors in relation to an established outcome. These studies are useful when large sets of high-quality data are available, but can be hindered by incomplete or sloppy records. While easily manipulated, retrospective studies can provide valuable insights into the relationships between variables. For example, a study by Chang et al. investigated changes in muscle size and their correlation with a history of chronic plantar fasciitis.
Reverse Linear Periodization
Reverse linear periodization is a type of periodization training that progresses from high-intensity training to low-intensity training. This strategy reverses the progression performed during conventional linear periodization and is often used to progress from strength or power development early in a program to muscular endurance or work capacity later in the training cycle.
Roll
Roll: Roll is an arthrokinematic motion. The movement of an object, usually in one direction (inferiorly, medially, etc.), by turning over and over on its axis. Similar to the way a ball might roll across a field. An anatomical example would be the posterior roll of the humeral head in the glenoid fossa during external rotation of the humerus.
S
Saddle Joint
Saddle Joint: The opposing surfaces are reciprocally concave-convex, allowing motion in 2 planes, similar to that of a horseback rider in a saddle.
Sagittal Plane
Sagittal Plane: The sagittal plane divides the body into left and right halves. Generally, sagittal plane motion refers to motion that is forward, backward, up, and down.
Sarcomere
Sarcomere: A segment of a myofibril (muscle cell) from one Z disk to the next. This is the smallest functional unit of a muscle cell.
Scapular Plane
Scapular Plane: The scapular plane is the plane of the scapula. This plane is medially rotated approximately 30-40 degrees from the frontal plane (between the frontal and sagittal planes).
Sensitivity
Sensitivity is a key concept in medical testing, measuring the probability that a positive test result accurately identifies someone with the disease or condition being tested for. A highly sensitive test can detect the presence of the disease in nearly all individuals who have it, while a less sensitive test may miss cases, leading to false negatives. Understanding sensitivity is critical in selecting appropriate testing methods and interpreting results. In this article, we explore the definition of sensitivity, how it's calculated, and its importance in medical testing.
Sets to Failure
Sets-to-failure is a resistance training strategy in which an individual performs repetitions of an exercise until they can no longer complete a repetition.
Sliding Filament Theory
The sliding filament theory explains the organization and structure of the sarcomere (the smallest function unit of a muscle cell) and the contractile proteins.
Specificity
Specificity is a critical aspect of medical testing that measures the probability of a negative test result in someone without a particular pathology. A highly specific test accurately identifies individuals with a specific disease while producing negative results for everyone without the disease. This ability to exclude healthy individuals from a diagnosis is crucial for minimizing false-positive results and ensuring appropriate treatment. Understanding specificity is essential for interpreting medical test results and making informed decisions about patient care.
Spin
Spin: Spin is an arthrokinematic motion. A rotational movement around a single axis. Analogous to the way a top or dreidel "spins" on a tabletop. An anatomical example would be the posterior spin of the femoral head in the acetabulum during hip flexion.
Stability
Stability refers to the ability of a body to produce forces that will restore equilibrium when disturbed. This property is essential for maintaining balance during exercises like a single leg chop, where small forces are required to keep the body stable while moving the load shifts the center of mass. Understanding stability is crucial for athletes, fitness enthusiasts, and physical therapists alike, as it can help prevent injuries and improve overall performance. Synonyms for stability include balance, equilibrium, steadiness, control.
Stability Training
Stability Training: An exercise or rehabilitation program designed to enhance the body's ability to stabilize (maintain or regain balance). A stability training program prioritizes exercise progression over increasing repetitions, sets, load, or speed.
Stabilizers (Muscle)
A stabilizer improves alignment between joint surfaces (arthrokinematics) during joint actions (osteokinematics).
Stretch Reflex
Stretch reflex is a neuromuscular reflex in which an increase in muscle length activates receptors known as muscle spindles, which signal an increase in muscle activity.
Stretch Shortening Cycle (SSC)
The stretch-shortening cycle is a coordinated sequence of quick eccentric (lengthening/pre-stretch), amortization (transition), and concentric (shortening) muscle actions that result in greater power output than is achieved if a quick pre-stretch does not precede a concentric contraction.
Superior
Superior: An anatomical direction that refers to a structure located "above" another structure. Generally, this term is used to describe the relative position of a structure when the body is in the anatomical position. For example, the nose is superior to the mouth.
Superset
Supersets: Performing two sets with little or no rest between sets. Supersets can include a pair of exercises for the same muscle, opposing muscles, upper and lower body, or a combination of techniques.
Supine
Supine: An anatomical position that refers to face up, palm(s) up, or lying on one's back (face up). For example, when performing the exercise "floor bridge" (Bridge and Progressions), the person is lying on their back in a supine position.
Synergistic Dominance
Synergistic dominance is an increase in synergistic muscle activity relative to a weak or inhibited prime mover. For example, inhibition of the gluteus maximus may lead to synergistic dominance of the biceps femoris during hip extension. This can lead to a range of symptoms, such as pain, discomfort, and limited range of motion. Causes of synergistic dominance include injury, poor posture, and muscle imbalances. Treatment options may include corrective exercise, physical therapy, and manual therapy. Synonyms for synergistic dominance include overactive synergists, compensatory movements, and altered movement patterns. Related terms include muscle imbalance, prime mover, and reciprocal inhibition.
Synergists (Muscle)
Synergists: Synergists are muscles that assist the prime mover in performing a joint action. By definition, all agonists that are not the prime mover are synergists.
Synovial Joint
Synovial joints are the most common joint type in the human body. Designed for motion, their unique structure includes a joint capsule, synovial fluid, and other components.
T
Taut Band
A taut band is a localized contracture of sarcomeres within a muscle without the activation of the motor endplate by an action potential. Taut bands are correlated with trigger point development.
Tension
Tension (physics) may be described as a pulling force transmitted axially, or an action-reaction pair of forces acting at each end of a structure. For example, muscular tension is the result of contractile proteins attempting to pull a muscle to a shorter length while being resisted by joints, connective tissue and external loads. Often this may be visualized as a "stretching" or "lengthening" force resulting in "tautness". The rope in a game of tug-of-war is a good example.
Test-Item Cluster
A test-item cluster is a specific group of special tests for a particular diagnosis that has greater accuracy than a single special test, as demonstrated by research.
Thoracolumbar Fascia (TLF)
The Thoracolumbar Fascia (TLF) is a dense, complex, multi-layer connective tissue structure that invests in the thoracic spine, lumbar spine, sacrum, iliac crest, sacrotuberous ligament, and several core muscles.
Tone
Tone refers to the resistance to stretch in resting muscle and the readiness with which the nervous system activates muscle in response to stimuli. This inherent quality of muscle can be felt as tissue resistance during manual techniques. Understanding and measuring muscle tone is important in the diagnosis and treatment of clinical muscle pain. Synonyms for tone include tonicity, muscle tone, muscular tone, and muscle tension. Related glossary terms include hypertonicity, hypotonicity, and muscle spasm.
Torque
Torque is a rotational force that causes an object to rotate around an axis. Linear force results in torque when applied to a lever that moves in a circle around an axis. In the human body, most muscles produce torque, because most bones move around the fixed axis of a joint. For example, during squats the gluteus maximus contracts (linear force), pulling the femur (lever), around the hip (axis), resulting in extension (a circular motion). Note, although "external rotation" and "internal rotation" includes "rotation" in the name of the action, all joint actions are the result of rotational torque forces.
Transverse Plane
Transverse Plane (Horizontal Plane): The transverse plane divides the body into top and bottom halves. Also referred to as the "horizontal plane," it may be helpful to remember that this is also the "plane of the horizon" or the "plane parallel to the horizon."
Trigger Point
Trigger Point: A hyper-irritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band.
True Negative
True negative is a term used in testing to describe the proportion of negatives in a group that were assessed correctly. 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, there are 4 possible results, because a positive or negative result could be right (true) or wrong (false).
True Positive
True positive is a term used in testing to describe the proportion of positive results that are correctly identified. 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, there are 4 possible results, because a positive or negative result could be right (true) or wrong (false).
Twitch Response
Twitch Response or LTR, is a sudden contraction of fibers within a taut band when strummed (manually), needled, or compressed with a vibration massage device. The contractions may be observed visually, recorded electromyographically (EMG), or visualized with diagnostic ultrasound (1). This phenomenon is widely studied and utilized in the diagnosis of myofascial trigger points (MTPs), a common cause of muscle pain. The ability to induce LTR can also be used to differentiate MTPs from other types of muscle pain. 1. Gerwin, R. D., & Duranleau, D. (1997). Ultrasound identification of the myofascial trigger point. Muscle & nerve, 20(6), 767-768.
U
Unilateral
Unilateral refers to "one side." It is a term used to describe movements or structures on one side of the body.
Upward Rotation (Scapula)
Scapular Upward Rotation: A joint action of the scapula (shoulder blades) where the inferior angle moves upward and outward, causing the glenoid fossa (shoulder socket) to tilt upward.
V
Validity
Validity refers to how well a test measures what it's supposed to measure. Types of validity include face validity, content validity, criterion validity, and construct validity.
Ventral
Ventral: An anatomical direction that refers to the front or lower side of the body. In humans, this term is almost exclusively used in reference to the front of the trunk and central nervous system. In human anatomy, synonyms include anterior or front.
Viscera
Viscus refers to the internal organs of the chest and abdomen, including the heart, lungs, liver, pancreas, and intestines. These organs play crucial roles in maintaining our bodily functions and keeping us alive. The viscera of the thoracic cavity (heart and lungs) are protected by the rib cage, while those in the abdomen are protected by the abdominal muscles.
Visual Analogue Scale (VAS)
Visual Analogue Scale (VAS) is a scale used to assign a number to a participant’s perceived level of discomfort, pain, severity, or exertion. This scale is usually a numbered line, from 0 – 10, on a piece of paper (visual), that allows a patient to identify the point along the line (analog) that best represents their experience. A fairly robust body of research has demonstrated the validity, sensitivity, and reliability of VAS scales for a variety of applications and populations.
Volar
Volar (Palmar): An anatomical direction that refers to the palm of the hand, the palm side of the forearm, and, less commonly, the sole of the foot. For example, the lumbrical muscles are located on the volar side of the metacarpals. When used in reference to the hand, a synonym for volar is palmar.