Glossary

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.  Example, arthrokinematic motion of the talus includes posterior glide on the tibia during ankle dorsiflexion.   Image: Clinical Gate. "Arthorkinematics." https://clinicalgate.com/getting-started. 3/18/2015. https://clinicalgate.com/wp-content/uploads/2015/03/B978032303989500002X_f001-008ab-9780323039895.jpgRead More...

Active Structure: 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. For example, active resistance to anterior translation during shoulder flexionRead More...

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 parallel arrangement of thicker filaments (myosin) and overlap with the thinner filaments (actin). As a muscle contracts, the A-band is where actin and myosin interact. Saladin, K. (2014). Anatomy & physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717 Image: Sameerb in English WP, Copyrighted free use, https://commons.wikimedia.org/w/index.php?curid=764619 Read More...

Accuracy: the proportion of individuals correctly identified by the test results. 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. Read More...

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.Read More...

Arthorkinematic Inhibition: 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.Read More...

Amortization Phase: 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. For example, the athlete was cued to spend as little time as possible at the bottom of their squat stance (the amortization phase) during a set of box jumps.Read More...

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. For 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.   Image: By BruceBlaus - Own work, CC BY 3.0,Read More...

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 ofRead More...

Appendicular Skeleton - The appendicular skeleton refers to the bones of the arms and legs and the bones that support them. This includes the pelvis, clavicle, and scapula. There are approximately 126 bones in the appendicular skeleton.  Etymology - Appendicular, as in appendage, "that which is appended to something as a proper part," 1640s, from append + -age. - Etymology Online "Appendicular skeleton" refers to a set of bones whose function is distinct from the bones of the "axial skeleton".Read More...

Action Potential:  A rapid change in voltage, resulting in a wave of excitation, that may result in stimulation of a nerve or muscle cell. 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/offRead More...

Algometry: measuring the amount of pressure to result in sensitivity or pain, using an algometer. 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.Read More...

Activation Technique: 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. 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. Activation techniques/exercises cannot be multi-joint movement patterns due to relative flexibility, altered reciprocal inhibition, and synergistic dominance resulting in compensation patterns. For example, the side-lying leg raise is a gluteus medius activation involving resisted hip abduction while minimizing the contributionRead More...

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

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. Example, arthrokinematic motion of the talus includes posterior glide on the tibia during ankle dorsiflexion. Read More...

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. Etymology - Appendicular, as in appendage, "that which is appended to something as a proper part," 1640s, from append + -age. - Etymology Online "Appendicular skeleton" is a label referring to a set of bones whose function is distinct from the bones of the "axial skeleton".Read More...

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. Energy is provided when hydrolysis results in the cleaving of a phophate group; resulting in adenosine diphosphate, an inorganigic phosphate group, and energy. Read More...

Axial Skeleton: Axial skeleton refers to the bones of the head, neck, trunk, and spinal column (does not include pelvis). There are approximately 80 bones in the axial skeleton. 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" - Etymology Online "Axial skeleton" is a label referring to a set of bones whose function is distinct from the bones of the "appendicular skeleton".Read More...

Anterior: An anatomical direction; toward the front of the body. For example, the face is on the anterior aspect of the head.Read More...

Antagonists: 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. For example, the triceps are antagonists to the biceps during elbow flexion.In the image of the row above, the anterior deltoid is the antagonist to the latisimmus doris (the prime mover) during shoulder extension.Read More...