muscle testing assessment

8/8/2019 Muscle Testing Assessment

1/4

Muscle testing is the evaluation of contractile units, including muscles and tendons, and theirability to generate forces.

Purpose-Muscle testing is indicated in any individual with suspected or actual impairedmuscle performance, including strength, power, or endurance. Impairments in muscle function

may result from cardiovascular, pulmonary, musculoskeletal or neuromuscular disease ordisorders. Identification of specific muscles or muscle groups with impaired function providesinformation for appropriate intervention, which may include strengthening exercises, functional

drills, bracing, or compensatory muscle use.

Precautions-It is important to determine the patient's ability to withstand the force to beapplied. The patient should have good cardiovascular function, be instructed against using theValsalva maneuver, and be positioned appropriately. Care should be taken with anybody part

that is under movement restriction due to fracture, post-surgical, or other tissue healing.

Forms of muscle testing include manual strength testing, functional tests, and dynamometry.

Manual muscle testing is a widely used form of muscle testing in the clinic. In this form oftesting, the individual is asked to hold a limb or other body part at the end of its available rangeor at another point in its range of motion while the clinician provides manual resistance. General

procedures include the following:

y The patient should be placed in a position that provides overall support to the body sothat he or she can concentrate his or her effort on the part being tested.

y The part to be tested initially is placed in an antigravity position. If muscles are too weakto function against gravity, they are then tested in the horizontal plane.

y The proximal part of the area being tested should be stabilized to reduce the opportunityfor compensatory action by muscles other than those being tested.

y Resistance needs to be applied directly opposite the "line of pull" of the muscles beingtested.

y Gradual, not sudden, application of pressure should take place, using a long lever arm inmost cases.

y Both sides should be assessed to provide a comparison, especially when one side isaffected by pathology and the other is not.

Grading of muscle tests is used to determine a patient's physical therapy diagnosis and in

assessing progress over time. Objective observation includes determining the patient's ability tohold a test position, move through a full range of motion, or to overcome gravity. Care must be

taken in grading, however, due to the inevitable subjectivity of muscle testing. Subjective factorsinclude the clinician's impression of how much resistance to apply and how much is tolerated.

Consistent testing procedures, including accurate joint placement and prohibition ofcompensatory movements, allow for increased reliability in using manual muscle testing as an

evaluation tool. In studies comparing manual testing and dynamometry, results show positivecorrelation; however, manual muscle testing is less sensitive than dynamometry.


2/4

Traditional grading has been described using either the terms "zero," "trace," "poor," "fair,""good," and "normal," or using a numerical scale from 0 through 5. When determining a grade,

first determine whether or not the patient can move the body part through its full range againstgravity and hold the body part in the test position. This ability results in a grade of fair, or 3, and

is the most objective observation made during testing due to the consistency of gravity. A poor

grade, or 2, is given when a patient is able to move the body part through its complete range ofmotion in the horizontal plane, that is, with the effect of gravity eliminated. A trace grade, or 1,is given when there is no visible movement through a part's range, but a slight contraction can be

palpated. When there is no evidence of even a slight contraction, a grade of zero is given.

Grades > fair are assessed with body part in specified test position. Grade of good, or 4, denotesability of patient to hold the body part in the test position against moderate pressure. A normal

grade, or 5, denotes that the patient holds body part against strong pressure by the clinician.

Pluses and minuses can be added to the above grades to further describe muscle ability, but somediscourage their use because it introduces even more subjectivity to grading. In some cases,

however, the use of a plus or minus grade provides important information. For example, a patientwith a fair grade (3) for a muscle group may not be able to use an orthosis effectively, but if that

patient achieves a fair plus (3+), he or she can withstand minimal resistance against gravity andtherefore may be able to tolerate the additional weight of an orthosis. Descriptors for plus and

minus grades are included in the summary of grades below:

y Normal (5): withstands strong pressure in test position.y Good plus (4+): withstands moderate to strong pressure.y Good (4): withstands moderate pressure.y Good minus (4): withstands slight to moderate pressure.y Fair plus (3+): withstands slight pressure. Fair (3): holds test position against gravity but

tolerates no additional pressure.y Fair minus (3): sags from test position or only moves through partial range of motion

against gravity (>50% of motion).y Poor plus (2+): moves through 50% of motion or less in antigravity position, or holds

against resistance in gravity-eliminated position (horizontal plane).y Poor (2): moves through complete range in horizontal plane.y Poor minus (2): moves through partial range in horizontal plane.y Trace (1): slight contraction, but no visible movement of body part detected.y Zero (0): complete lack of muscle contraction.

It is important to note that manual muscle grades are an ordinal level of measurement, meaningthat the categories do not represent equal magnitudes. In other words, the strength required to

move from zero to trace is different from the amount of strength required to move from good tonormal. Therefore, manual muscle grades are not useful for arithmetical computations.

Manual muscle testing is a relatively quick and inexpensive method of evaluating strength;however, results often do not denote a person's ability to perform functional activities. In

addition, a normal muscle grade does not necessarily indicate a patient's ability to return to his or


3/4

her normal level of activity, especially if it includes sports participation. This ability is bettertested with functional tests.

Functional muscle testing allows for the assessment of muscles to perform components of,or entire, tasks related to daily activities. Functional tests look at the ability of muscle groups to

decelerate, stabilize or accelerate movement in all three planes of motion in a measurable way.Specific tests can be chosen to look at movements at specific joints or those that are dominant ina certain plane of motion. For example, a single-leg squat provides valuable information about

the quadriceps' performance. An anterior jump test provides the same type of information on amore challenging level for the patient.

Categories of fnxl muscle testing include following: balance, excursion, lunge, step-up, step-

down, jump and hop tests. In performing tests, patient safety is key. Clinical judgment should beused to determine when fnxl testing is appropriate; for example, a person with a weight-bearing

restriction should not perform a balance test on that lower extremity. Testing should be done in aprogressive manner; for example, a balance test should be performed before an excursion test, a

straight plane lunge test before a rotational lunge test. Tests can be used to document progress bymeasuring distance of reach, time, degrees of excursion, etc., as appropriate to specific test.

Dynamometry-Isokinetic dynamometry uses a device that measures the force used incontraction of a muscle group. The device is able to apply maximal resistance at all points in thebody part's range of motion at a specified speed. Isokinetic testing can be used to objectively

assess strength, power and endurance. Strength is assessed using slow velocity testing to look atpeak torques produced. Power testing uses fast velocity settings to look at the amount of work

performed during a particular amount of time. Endurance testing looks at the patient's ability tomaintain sorce output during numerous repetitions at high velocities.

Manual muscle testinglevels of muscle performance

Performance Level Definition

Normal Completes full ROM against gravity; holds test position against strong

pressure.

Good Completes full ROM against gravity; holds test position against moderateto strong pressure.

Fair Completes full range of motion against gravity, and holds test positionwith slight or no added pressure. There may a gradual release from test

position.

Poor Completes partial range of motion against gravity, and moves throughcomplete range of motion in horizontal plane.

Poor-Trace Completes partial range of motion in horizontal plane.No visible movement of the part, but examiner may observe or palpate

contractile activity in the muscle.

Zero No contraction detected in the muscle.


4/4

Advantages of isokinetic testing include the ability to maximally load the muscle throughout itsrange of motion; stabilization of proximal body parts to prevent substitute motions; measurement

of concentric and eccentric loading; and objectivity. As in manual muscle testing, however,isokinetic testing does not necessarily provide an accurate picture of how a muscle will function

during actual activities of daily living or sports. In addition, unlike manual muscle testing, it

requires expensive equipment and space.

Hand-held and grip dynamometers are smaller, less expensive alternatives for measuring muscle

strength in an objective manner. Information regarding force produced during a contraction suchas knee extension or hand grip is displayed in units (often pounds) on a display or dial. Use of

these instruments, however, is limited to the body parts they were designed to measure; i.e., agrip dynamometer is useful only for measuring grip strength.

KEY TERMS

Valsalva maneuverForced expiratory effort against a closed airway, usually used during

strenuous effort.

Results

Results are recorded as described above, by the use of grades or force units. Regardless of thetype of muscle testing used, the results can be used to help determine specific sites of

impairment, in addition to providing data for assessing progress.

Health Care Team Roles

Muscle testing is performed by physicians, especially orthopedic doctors and physiatrists, inaddition to physical therapists and occupational therapists. Manual muscle testing often is an

integral part of a PT or OT evaluation of muscle function. The following knowledge is requiredfor any health care practitioner to perform an accurate test:

y location, origin and insertion of muscle(s) being testedy direction of muscle fiber orientationy function of muscle being tested, in addition to functions of its synergists and antagonistsy appropriate positioning for the testy recognition of substitution or compensation by other musclesy recognition of the effects of factors such as restricted range of motion and painy specific contraindicationsy ability to palpate muscle contractiony ability to modify a test due to inability to attain a certain positiony ability to communicate to the patient regarding purpose, procedures and patient

requirements for the test

muscle testing assessment

Documents