Manual muscle testing

SHARMIN SUSIWALA
MANUAL MUSCLE TESTING
Definition
Muscle testing is the evaluation of contractile units, including muscles and tendons, and their ability to
generate forces.
Purpose
Muscle testing is indicated in any individual with suspected or actual impaired muscle performance,
including strength, power, or endurance. Impairments in muscle function may result from cardiovascular,
pulmonary, musculoskeletal or neuromuscular disease or disorders. Identification of specific muscles or
muscle groups with impaired function provides information 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 be applied. The patient should
have good cardiovascular function, be instructed against using the Valsalva maneuver, and be positioned
appropriately. Care should be taken with any body 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
Manual muscle strength testing is a widely used form of muscle testing in the clinic. In this form of testing, the
individual is asked to hold a limb or other body part at the end of its available range or at another point in its range
of motion while the clinician provides manual resistance. General procedures include the following:
The patient should be placed in a position that provides overall support to the body so that he or she can concentrate
his or her effort on the part being tested.
The part to be tested initially is placed in an antigravity position. If muscles are too weak to function against gravity,
they are then tested in the horizontal plane.
The proximal part of the area being tested should be stabilized to reduce the opportunity for compensatory action by
muscles other than those being tested.
Resistance needs to be applied directly opposite the "line of pull" of the muscles being tested.
Gradual, not sudden, application of pressure should take place, using a long lever arm in most cases.
Both sides should be assessed to provide a comparison, especially when one side is affected 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 to hold 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 factors include the clinician's impression of how much resistance to apply and how
much is tolerated. Consistent testing procedures, including accurate joint placement and prohibition of compensatory
movements, allow for increased reliability in using manual muscle testing as an evaluation tool. In studies
comparing manual testing and dynamometry, results show positive correlation; however, manual muscle testing is
less sensitive than dynamometry.
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 against gravity 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

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gravity. A poor grade, or 2, is given when a patient is able to move the body part through its complete range of
motion 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 above fair are assessed with the body part in the specified test position. A grade of good, or 4, denotes the
ability of the patient to hold the body part in the test position against moderate pressure. A normal grade, or 5,
denotes that the patient holds the body part against strong pressure by the clinician.
Pluses and minuses can be added to the above grades to further describe muscle ability, but some discourage 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 patient with 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 and therefore 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:
Normal (5): withstands strong pressure in test position.
Good plus (4+): withstands moderate to strong pressure.
Good (4): withstands moderate pressure.
Good minus (4-): withstands slight to moderate pressure.
Fair plus (3+): withstands slight pressure.
Fair (3): holds test position against gravity but tolerates no additional pressure.
This therapist is testing the muscles of the patient's hand by pressing on the thumb. (Photograph by John Watney.
Science Source/Photo Researcherso. Reproduced by permission.)
Fair minus (3-): sags from test position or only moves through partial range of motion against gravity (>50% of
motion).
Poor plus (2+): moves through 50% of motion or less in antigravity position, or holds against resistance in gravity-eliminated
position (horizontal plane).
Poor (2): moves through complete range in horizontal plane.
Poor minus (2-): moves through partial range in horizontal plane.
Trace (1): slight contraction, but no visible movement of body part detected.
Zero (0): complete lack of muscle contraction.
It is important to note that manual muscle grades are an ordinal level of measurement, meaning that 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 to normal. 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 her normal level of activity, especially if it includes sports participation.
This ability is better tested with functional tests.
Functional muscle testing
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 in a 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 a
more challenging level for the patient.
Categories of functional muscle testing include the following: balance, excursion, lunge, step-up, step-down, jump
and hop tests. In performing tests, patient safety is key. Clinical judgment should be used to determine when
functional testing is appropriate; for example, a person with a weight-bearing restriction should not perform a

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balance test on that lower extremity. Testing should be done in a progressive 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 by measuring distance of reach, time, degrees of excursion, etc., as appropriate to the
specific test.
Dynamometry
Isokinetic dynamometry uses a device that measures the force used in contraction of a muscle group. The device is
able to apply maximal resistance at all points in the body 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 at peak 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 to maintain sorce
output during numerous repetitions at high velocities.
Advantages of isokinetic testing include the ability to maximally load the muscle throughout its range 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 such as 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., a grip dynamometer is useful only for measuring grip strength.
Manual muscle testing—levels of muscle performance
Normal: Completes full range of motion against gravity, and holds test position against strong
pressure.
Good: Completes full range of motion against gravity, and holds test position against moderate
to strong pressure.
Fair: Completes full range of motion against gravity, and holds test position with slight or no
added pressure. There may a gradual release from test position.
Poor: Completes partial range of motion against gravity, and moves through complete 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.
specific sites of impairment, in addition to providing data for assessing progress.
Assessment
Muscle testing is performed by physicians, especially orthopedic doctors and physiatrists, in addition 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 required for any health care practitioner to
perform an accurate test:
location, origin and insertion of muscle(s) being tested
direction of muscle fiber orientation
function of muscle being tested, in addition to functions of its synergists and
antagonists
appropriate positioning for the test

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recognition of substitution or compensation by other muscles
recognition of the effects of factors such as restricted range of motion and
pain
specific contraindications
ability to palpate muscle contraction
ability to modify a test due to inability to attain a certain position
ability to communicate to the patient regarding purpose, procedures and
patient requirements for the test

Manual muscle testing

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Manual muscle testing