Module 3.2: Manual Muscle Testing and Muscle Performance

Vocabulary flashcards covering manual muscle testing principles, muscle architecture, fiber recruitment, insufficiencies, and the Kendall/Pedretti grading criteria.

Pennate Muscles

Muscles with fibers oriented obliquely (slanted) relative to the line of force that generate greater force due to increased physiological cross-sectional area; subtypes include unipennate, bipennate, and multipennate.

Fusiform Muscles

Muscles whose fibers are arranged parallel to the line of force, allowing for a greater range of motion (ROM) rather than maximal force production.

Physiological Cross-Sectional Area (PCSA)

The cross-sectional area of a muscle perpendicular to its fibers; wider muscles possess a greater number of available contracting fibers, increasing force capacity.

Passive Insufficiency

The inability of a multi-joint muscle to elongate sufficiently to permit full, simultaneous joint range of motion across every joint it crosses.

Active Insufficiency

A condition occurring when adjacent muscle fibers of a multi-joint muscle are maximally shortened, preventing the muscle from generating further force or maintaining active contraction.

Force-Velocity Relationship

The relationship dictating that when a muscle contracts (concentrically or eccentrically), the rate of muscle length change (load rate) directly influences its maximal force potential.

Muscle Power

Force exerted over a distance per unit of time; a velocity-dependent parameter predominantly utilizing Type II muscle fibers (specifically Type IIb/x).

Muscle Strength

The maximum force that a muscle can develop and exert during a single muscle contraction; governed predominantly by Type IIa muscle fibers interacting with neurologic, biomechanical, and cognitive systems.

Muscle Endurance

The ability of a muscle group to repetitively exert force against a submaximal load or sustain a submaximal contraction over an extended duration; predominantly relies on Type I muscle fibers.

Manual Muscle Testing (MMT)

A standardized clinical procedure evaluating muscle strength based on the ability to move a joint against gravity and hold against manual resistance.

Break Test

An isometric muscle test in which the client holds a joint in a mechanically advantaged position for the primary agonist(s) while external resistance is applied until the hold breaks.

Make Test

A strength assessment method where a concentric contraction is performed while manual or dynamometric resistance is applied continuously throughout the active range of motion.

Basic Muscle Strength Screening

A quick screening performed in positions of convenience (such as a bed or wheelchair) where a client holds a position against resistance to determine whether formal MMT is required.

MMT Grade 5 (Normal)

The muscle moves the joint through full active range of motion against gravity and holds the test position against maximal or strong manual resistance.

MMT Grade 4 (Good)

The muscle achieves full active range of motion against gravity and holds the test position against moderate manual resistance.

MMT Grade 3+ (Fair Plus)

The muscle completes full active range of motion against gravity and successfully holds against slight or minimal manual resistance.

MMT Grade 3 (Fair)

The muscle achieves full active range of motion against gravity but cannot hold against any added manual resistance.

MMT Grade 3- (Fair Minus)

The muscle achieves partial active range of motion ($\ge 50\%$ but $< 100\%$) against gravity with a gradual release from the test position.

MMT Grade 2+ (Poor Plus)

The muscle completes full active range of motion in a gravity-reduced (horizontal) plane and holds against slight resistance, or completes less than $50\%$ active range of motion against gravity.

MMT Grade 2 (Poor)

The muscle moves the joint through complete active range of motion in a gravity-reduced (horizontal) plane with no additional resistance.

MMT Grade 2- (Poor Minus)

The muscle moves the joint through only partial active range of motion in a gravity-reduced (horizontal) position.

MMT Grade 1 (Trace)

No active joint motion is produced in any position, but muscle contraction or tendon tension is visually observed or palpated.

MMT Grade 0 (Zero)

Complete absence of joint motion and no observable or palpable muscle contraction in both against-gravity and gravity-reduced positions.

True Effort

The maximal voluntary physical exertion displayed by a client, which may be constrained by pain, fear of injury, poor instructional comprehension, or low self-efficacy.

MMT Contraindications

Conditions prohibiting manual muscle testing, including bone cancer in the tested area, acute unhealed fractures, tendon or muscle disruptions, severe pain, and significant spasticity.