Principles of Manual Muscle Testing

Mazyad Alotaibi

Test and measurementsThis 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 testingDefinition:

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 testingThe 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 testingMuscular 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 testingMuscular 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 testingRange 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

Inner range

Middle 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 testingA- 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 testingB- 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.

ValidityDefinition of validity:

Means that a test actually measures what it is suppose to measure.

ReliabilityDefinition 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.

ReliabilityTypes 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 testThere 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 testingThe 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 testingThe 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 testingThe 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 testingThe 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 testingThe 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 testingThe grade 0 (Zero) Muscle:

Muscle is completely quiescent on palpation or visual inspection.

Plus (+) and Minus (-) GradesUse 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 testsObservation 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 testThe 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.