Principles of Manual Muscle
Testing
Mazyad Alotaibi
Test and measurements
This course consists of theoretical and laboratory sessions, which designed to give
the student the skills and knowledge necessary to perform:
A- Muscle test
a complete manual muscle test procedures.
B- Range of motion
Utilizing a goniometer to measure the range of motion
for all joints in the body.
C- Length and circumference
Length and circumference measurements using a
tape measure.
Manual muscle testing
Definition:
Is a procedure for the evaluation of the function and strength of individual muscles and
muscles group based on effective performance of a movement in relation to the
forces of gravity and manual resistance through the availble ROM.
Manual muscle testing
The purpose of muscle test:
 Is to provide information that may be of assistance to a number of health professional
in differential diagnosis, treatment planning and prognosis.
 To assess muscle strength, the therapist must have a sound knowledge of anatomy
and surface anatomy.
 The therapist must be a keen observer and be experienced in muscle testing to detect
minimal muscle concentration, movement, and or muscle wasting and substitution or
trick movements.
 A consistent method of manually testing muscle strength is essential to assess
accurately a patient’s present status, progress, and the effectiveness, of the treatment
program.
Manual
muscle
testing
Muscular strength:
 The maximal amount of tension or force that a muscle or muscle group can voluntary
exert in one maximal effort, when type of muscle contraction, limb velocity, and joint
angle are specified.
Manual muscle testing
Muscular endurance:
 The ability of a muscle or muscle group to perform repeated contraction, against
resistance, or maintain the an isometric contraction for a period of time.
Manual muscle testing
Range of muscle work:
The full range in which a muscle work refers to the muscle changing from a position
of full stretch and contracting to a position of maximal shortening. The full range is
divided into part, outer, inner, and middle ranges.
Outer
range
Middle
range
Inner
range
Range of muscle work
Outer range:
Is from a position where the muscle is on full stretch to a position half
way though the full range of motion.
Inner range:
is from a position halfway through the full range to a position where
the muscle is fully shortened.
Middle range:
is the portion of the full range between the mid-point of the outer
range and the midpoint of the inner range.
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Types of muscle contraction
A- isometric contraction:
When there is tension developed in the muscle but no movement occurs, the origin
and insertion of the muscle do not change position, and the muscle length does not
change.
Types of muscle contraction
B- isotonic contraction:
The muscle develops constant tension against a load or resistance.
 Concentric contraction:
Tension is developed in the muscle and the origin and insertion of the muscle move
closer together, the muscle shortens.
 Eccentric contraction:
Tension is developed in the muscle and the origin and insertion of the muscle move
farther a part, the muscle lengthens.
Functional classification of muscle
Muscle may be categorized as follows:
Prim mover or agonist:
A muscle or muscle group that makes the major contribution to movement at the joint.
Antagonist:
A muscle or muscle group that has an opposite action to the prime mover’s.
Synergist:
A muscle that contraction and works a long with the agonist to produce the desired
movement.
Functional classification of muscle
Synergist:
A muscle that contraction and works a long with the agonist to produce the desired
movement. Three types of synergists are:
1- Neutralizing or counter acting synergists:
Muscles contracted to prevent unwanted movements produced by the prim mover.
2- Conjoint synergists:
Two or more muscles that work together to produce the desired movement.
3- Stabilizing or fixating synergist:
Muscle that prevent movement or control the movement at joints proximal to the
moving joint to provide a fixed or stable base from which the distal moving
segment can effectively work.
Muscle testing assessment procedure
1- Explanation and instruction:
The therapist demonstrate and or explains briefly the movement to be
performed and or passively moves the patient’s limb through the test
movement.
2- Assessment of normal muscle strength:
Initially assess and record the strength of the uninvolved limb to determine the
patients normal strength.
3- Patient position:
The patient is positioned to isolate the muscle or muscle group to be tested in
either gravity eliminated or against gravity position.
Muscle testing assessment procedure
4- Stabilization:
Stabilize the site of attachment of the origin of the muscle so that the muscle has a fixed
point from which to pull. Prevent substitution and trick movements by making use of
the following methods:
A- the patient’s normal muscles.
B- the patient’s body weight.
C- the patient position.
D- external forces.
5- Substitution and trick movements:
When muscles are weak or paralyzed, other muscles may take over or gravity may be
used to perform the movements normally carried out by the weak muscles.
Conventional methods
Manual grading of muscle strength is based on three factors:
1- Evidence of contraction:
No palpable or observation muscle contraction (grade 0) or a palpable or
observable muscle contraction and no joint motion (grade 1).
2- Gravity as a resistance:
The ability to move the part through the full available range of motion gravity
eliminated (grade 2) or against gravity (grade 3) the most objective part of test.
3- Amount of manual resistance:
The ability to move the part through the full available range of motion against
gravity and against manual resistance (grade 4) or maximal manual resistance
(grade5).
Types of muscle testing
A- Break test
Manual resistance is applied to a limb or other body part after it has completed
its range of movement or after it has been placed at end range by the examiner.
Manual resistance should always be applied in the direction of the line of pull of
the participating muscle or muscles. At the end of the available range, or a point
in the range where the muscle is most challenged, the patient is asked to hold the
part at that point and not allow the examiner to break the hold with manual
resistance.
Types of muscle testing
B- Active resistance test
An alternative to the break test is the application of manual resistance against an
actively contracting muscle or muscle group (i.e., against the direction of the
movement as if to prevent that movement). During the motion, the examiner
gradually increases the amount of manual resistance until it reaches the maximal
level the subject can tolerate and motion ceases.
The examiner and the value of the muscle
test
The knowledge and skill of the examiner determine the accuracy and defensibility
of a manual muscle test. Specific aspects of these qualities include the following:
 Knowledge of the location and anatomical features of the muscles in a test.
 Knowledge of the direction of muscle fibers and their line of pull in each muscle.
 Consistent use of a standardized method for each different test.
 Consistent use of proper positioning and stabilization techniques for each test
procedure.
 Ability to identify pattern of substitution in a given test and how they can be
detected based on a knowledge of which other muscles can be substituted for one
(s) being tested.
The examiner and the value of the muscle
test
 Ability to detect contractile activity during both contraction and relaxation,
especially in minimally active muscle.
 Sensitivity to differences in contour and bulk of the muscles being tested in
contrast to the contra-lateral side or to normal expectations based on such
things as body size, occupation, or leisure work.
 Awareness of any deviation from normal values for range of motion and the
presence of any joint laxity or deformity.
 Understanding that the muscle belly must not be grasped at any time during a
manual muscle test except specifically to asses tenderness or pain and muscle
mass.
The examiner and the value of the muscle
test
 Ability to identify muscles with the same innervation, which will ensure a
comprehensive muscle evaluation and accurate interpretation of test results.
 Knowledge of the relationship of the diagnosis to the sequence and extent of the
test.
 Ability to modify test procedures when necessary while not compromising the
test result and understanding the influencing of the modification on the result.
 Knowledge of the effect of fatigue on the test results, especially muscles tested
late in a long testing session, and a sensitivity to fatigue in certain diagnostic
conditions such as myathenia gravis or eaton- lambert syndrome.
 Understanding of the effect of sensory loss on movement.
Validity
Definition of validity:
Means that a test actually measures what it is suppose to measure.
Reliability
Definition of reliability:
Is the repeatability and the extent to each comparable results are achieved every time a
test repeated. If a muscle test is repeated by one or more therapist who obtain the
same grade every time, then the test is reliable.
Reliability
Types of reliability:
1- Interrater reliability means that another person who performs the test should arrive at
same results, to an acceptable extend.
2- Intrarater reliability means that one person should come up with the same results on
every repetition of the test within acceptable level.
Influence of the patient on the test
 There may be variation in the assessment of the true effort expended by a patient
in a given test.
 The patient’s willingness to endure discomfort or pain may vary.
 The patient’s ability to understand the test requirements may be limited in some
case because of comprehension and language barriers.
 The motor skills for the test may be beyond some patient.
 Lassitude and depression may cause the patient to be indifferent to the test and the
examiner.
 Cultural, social, and gender issues may be associated with palpation and exposure
of a body part for testing.
 Though not an individual variation but causing considering differences in grading
are the size and non-comparability between big versus small muscles.
The grading system
Grades for a manual muscle test are recorded as numerical scores ranging from
(0), which represents no activity, to five(5), which represents a normal or
best possible response to the test or as great a response as can be evaluated
by a manual muscle test. Each numerical grade can be paired with a word
that describes the test performance in quantitative terms.
The grading system
Numerical score
Qualitative score
5
Normal (N)
4
Good (G)
3
Fair (F)
2
Poor (P)
1
Trace (T)
0
Zero (no activity) (0)
Grades of muscle testing
The grade 5 (Normal) Muscle:
The patient has an ability to complete a full range of motion or maintain end-point
range against gravity and maximal resistance.
Grades of muscle testing
The grade 4 (Good) Muscle:
The patient has an ability to complete a full range of motion against gravity and can
tolerate strong resistance without breaking the test position
Grades of muscle testing
The grade 3 (Fair) Muscle:
The grade 3 muscle test is based on an objective measure. The patient has an ability to
complete a full range of motion against only the resistance of gravity.
Grades of muscle testing
The grade 2 (Poor) Muscle:
The patient has an ability to complete a full range of motion in a position that
minimizes the force of gravity. This position often is described as the horizontal
plane of motion.
Grades of muscle testing
The grade 1 (Trace) Muscle:
The examiner can detect visually or by palpation some contractile activity in one or
more of the muscles that participate in the movement being tested.
Grades of muscle testing
The grade 0 (Zero) Muscle:
Muscle is completely quiescent on palpation or visual inspection.
Plus (+) and Minus (-) Grades
 Use of a plus or minus addition to a MMT grade is discouraged except in three
istances- Fair +, poor + and poor –
 Fair Plus 3+: The subject completes ROM against gravity with only minimal
resistance
 Poor Plus 2+: The subject is able to initiate movement against gravity
 Poor Minus 2-: The subject does not complete ROM in a gravity eliminated
position
Screening tests
Observation of the patient before the examination will provide valuable clues to
muscular weakness and performance deficits. For example, the examiner can:
 Watch the patient as he or she enters the treatment area to detect gross abnormalities
of gait.
 Watch the patient sit and rise from a chair, fill out admission or history forms, or
remove street clothing.
 Ask the seemingly normal patient to walk on the toes and then on the heels.
 Ask the patient to grip the examiner’s hand.
 Perform gross checks of bilateral muscle groups.
Preparing for the muscle test
The examiner and the patient must work in harmony if the test session is to be
successful, some basic principles should be present:
1- The patient should be as free as possible from discomfort or pain for the duration
of each test.
2- The environment for testing should be quiet. The temperature should be
comfortable for the partially disrobed subject.
3- The plinth or mat table for testing must be firm to help stabilize the part being
tested.
4- Patient position should be carefully organized so that position changes in a test
sequence are minimized.
5- All materials needed for the test must be at hand. This is particularly important
when the patient is anxious for any reason or is too weak to be safely left
untended.