Introduction to Manual Muscle Testing

1. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
Course Syllabus: Kerala University of Health Sciences (KUHS) BOT Programme
2020
Course Code: 022
Year: First (I) BOT
Subject: 105: Introduction to Occupational Therapy and Therapeutic Activities
Section A: Introduction to Occupational Therapy
Lecture: Module VIII: Overview of Assessments: Muscle Strength
References
1. Florence Peterson Kendall, Elizabeth Kendall McCreary, Patricia Gelse Provance, Mary
Mclntyre Rodgers, William Anthony Romani. Muscles Testing and Function with Posture and
Pain. 5th
Edition. 2005. Lippincott Williams & Wilkins. [Chapter 1: Fundamental Concepts.
Pages: 1-48.]
2. Radomski MV, Trombly Latham CA. Occupational Therapy for Physical Dysfunction. 7th
Edition. 2014. Lippincott Williams & Wilkins, a Wolters Kluwer Business. [Section II. Chapter
7: Assessing Abilities and Capacities: Range of Motion, Strength, and Endurance. Pages: 144-
241.]
3. Helen J. Hislop, Jacqueline Montgomery. Daniels and Worthingham’s Muscle Testing:
Techniques of Manual Examination. 8th
Edition. 2007. Saunders Elsevier. [Chapter 1:
Principles of Manual Muscle Testing. Pages 1-12.]
4. Pendleton HM, Schultz-Krohn W. Pedretti’s Occupational Therapy: Practice Skills for
Physical Dysfunction. 7th Edition. 2013. Elsevier Mosby. [Part IV: Chapter 22: Evaluation of
Muscle Strength. Pages: 529-537.]
5. Donna Latella, Catherine Meriano. Occupational Therapy Manual for Evaluation of Range
of Motion and Muscle Strength. 1st
Edition. 2003. Delmar, Cengage Learning. [Chapter 2:
Gross Manual Muscle Testing. Section 2-1: Introduction to gross manual muscle testing. Pages:
65-67.]
6. Reese NB, Bandy WD. Joint Range of Motion and Muscle Length Testing. 3rd Edition.
2017. Elsevier, Inc. [Section I. Chapter 1: Measurement of Range of Motion and Muscle
Length: Background, History, and Basic Principles. Pages: 3-28.]

2. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
Introduction1
I. Definition
Muscular Strength2
: the “ability of the muscle to exert force,” is a key component of muscular
fitness. (American College of Sports Medicine)
Muscle Strength is the ability of a muscle or group of muscles to produce tension and a resulting
force during a maximal effort, either statically (isometrically) or dynamically (isotonically) in
relation to the demands placed upon it.
Manual Muscle Strength Testing1
: Muscle strength testing is used to determine the capability
of muscles or muscle groups to function in movement and their ability to provide stability and
support.
Maximum Voluntary Contraction (MVC)2
: the maximum amount of tension that can be
produced under voluntary control, is commonly used to measure strength.
Because muscle testing is a measurement of voluntary contraction of an isolated muscle or
muscle group, strength testing is inappropriate for patients who lack the ability to contract a
single muscle or a muscle group in isolation such as patients who exhibit patterned movement.
II. Types of Muscle Strength Testing
1. Subjective: Manual muscle strength testing by using Medical Research Council (1976)
Oxford Grading System
2. Objective: By using objective instruments such as:
a. Electronic Manual Muscle Testing Device
b. Dynamometers e.g., Hand Held Jamar Dynamometer, Back Leg Chest Dynamometer,
Pinchmeter, Vigorometer and Sphygmomanometer.
III. Terms Used in Manual Muscle Strength Testing1
1. Patient
Important Factors: to consider whilst manual muscle strength testing of the patients are:
position of the patient, comfort of the patient, intelligent handing of muscles being tested and
stabilization of the proximal part of the body not being tested.

3. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
2. Fixation/Stabilization
Adequate Fixation: during assessment depends upon firmness of examining table, body
weight, firmness or stability of the body or body part and stabilization of the proximal part by
the examiner.
3. Muscle Strength Testing
• Passive Range of Motion Testing shall be performed prior to manual muscle strength
testing to distinguish between restriction of range of motion from muscle weakness.
• Joint Stability Assessment shall precede manual muscle strength testing to distinguish
between joint instability from muscle weakness.
4. Test Position
• Test Position: is the position in which the part is placed by the examiner and held (if
possible) by the patient. It is the position used for the purpose of evaluating muscle strength
for most muscles for example: supine lying, prone lying, side-lying, sitting and standing.
• Test Position: determines precision in positioning and accuracy in testing, detect
substitution movements (visible shift from the test position indicates a substitution movement)
and aids in grading the muscle strength in gravity eliminated, gravity assisted or against gravity
positions.
• One Joint-Muscle: optimal test position is at the completion of range for one-joint muscles
• Two Joint-Muscle: optimal test position for two or multi-joint muscles is at midrange of
overall length, in accordance with the length-tension principle.
5. Test Movement
• Test Movement is a movement of the part in a specified direction and through a specific
arc of motion.
• For accurate testing, the examiner should place the part in precisely the desired test position,
instead on explaining verbally or imitating a movement.
• Test Movement may be assessed in gravity eliminated, gravity assisted or against gravity
planes.

4. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
6. Pressure and Resistance1,3
Pressure: external force that is applied by the examiner to determine the strength of the muscle
holding in the test position. The placement, direction, and amount of pressure are important
factors when testing for strength above the grade of fair (3).
Whilst applying pressure, using a long lever gives the examiner a mechanical advantage and
allows more sensitive grading of muscle strength.
Manual grading of muscle strength is a subjective evaluation based on the amount of pressure
applied.
Resistance: external force that opposes the test movement. The resistance may be the force of
gravity or a force that is supplied by the examiner. Resistance may vary according to the
patient’s body weight and the examiner’s built.1
The term "resistance" is always used to denote a force that acts in opposition to a contracting
muscle. Manual resistance should always be applied in the direction of the "line of pull" of the
participating muscle or muscles.3
7. Substitution
Substitution results from one or more muscles attempting to compensate for the lack of
strength in another muscle or group of muscles.
Substitution is a good indication that the tested muscle is weak, that adequate fixation has not
been applied, or that the subject has not been given adequate instruction concerning how to
perform the test.
8. Weakness
Weakness is a range of strength from zero (0) to fair (3) in non-weight-bearing muscles and
fair+ (3+) in weight-bearing muscles.
Weakness will result in loss of movement if the muscle cannot contract sufficiently to move
the part through partial or complete range of motion.
Weakness may be presented by clients/patients due to varied causes e.g., nerve injury or
condition, disuse weakness (atrophy), stretch or strain weakness, pain or fatigue etc.

5. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
9. Shortness
Shortness (Tightness) is loss of motion when the muscle cannot be elongated through its full
range of motion. Shortness refers to a degree of shortness that results in slight to moderate loss
of range of motion.
10. Contracture
Contracture refers to a degree of shortness that results in a marked loss of range of motion.
11. Muscle Strength Grading
There are many manual muscle strength grading systems. Robert W. Lovett, M.D., introduced
a method of testing and grading muscle strength using gravity as resistance.
Lovett system was published in 1932 and listed the following definitions:
Gone: no contraction felt.
Trace: muscle can be felt to tighten but cannot produce movement.
Poor: produces movement with gravity eliminated but cannot function against gravity.
Fair: can raise the part against gravity.
Good: can raise the part against outside resistance as well as against gravity.
Normal: can overcome a greater amount of resistance than a good muscle.
The Kendalls system introduced the use of numbers for computing the amount of change in
muscle strength when doing research with patients recovering from poliomyelitis.
Muscle Strength Testing Grading System2
Numerical
Grade*
Descriptive
Grade
Definition
5 Normal The part moves through full ROM against gravity and takes
maximal resistance.
4 Good The part moves through full ROM against gravity and takes
moderate resistance.
4- Good Minus The part moves through full ROM against gravity and takes less
than moderate resistance.
3+ Fair Plus The part moves through full ROM against gravity and takes
minimal resistance before it breaks.

6. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
3 Fair The part moves through full ROM against gravity and is unable to
take any added resistance.
3- Fair Minus The part moves less than full ROM against gravity.
2+ Poor Plus The part moves through full ROM in a gravity-eliminated plane,
takes minimal resistance, and then breaks.
2 Poor The part moves through full ROM in a gravity-eliminated plane
with no added resistance.
2- Poor Minus The part moves less than full ROM in a gravity-eliminated plane,
no resistance.
1 Trace Tension is palpated in the muscle or tendon, but no motion occurs
at the joint.
0 Zero No tension is palpated in the muscle or tendon, and no motion
occurs.
*The Medical Research Council (1976) Oxford System for Manual Muscle Strength Testing
12. 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. At the end of
the available range, or at 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.3
13. 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). This may be called an "active resistance" test.
During the motion, the examiner gradually increases the amount of manual resistance until it
reaches the maximal level the subject/patient can tolerate and motion ceases.3
IV. Procedure and Steps of Manual Muscle Strength Testing2
1. Explain the procedure and demonstrate the desired movement.
2. Position the patient so that the direction of movement will be against gravity.
3. Stabilize proximal to the joint that will move to prevent substitutions.

7. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
4. Instruct the patient to move actively to the end position. If the patient cannot move actively
against gravity, place the patient in a gravity-eliminated position, and ask him or her to move
actively in this position.
5. Holding of Contraction: If the patient can move actively against gravity, tell the patient to
hold the contraction at the end position.
6. Apply Resistance: ● to the distal end of the segment into which the muscle inserts ● in the
direction the movement came from ● by starting with light resistance and increasing to
maximal resistance over a 2- to 3-second period
7. Palpate over the prime mover to determine whether the muscle is contracting or whether
gravity and/or synergistic muscles are substituting.
8. Record the appropriate grade according to the resistance tolerated before the muscle broke
or by the amount of movement achieved without resistance in an against-gravity or gravity-
eliminated position
V. Principles of Manual Muscle Strength Testing
1. Knowledge of the location and functions of the muscle or group of muscles (origin, insertion,
action, nerve supply with root values) and anatomical features of the muscle/muscles being
tested is a pre-requisite prior to initiating muscle strength testing. Ability of an
examiner/therapist to appreciate muscle contraction with its direction of pull, on palpation and
to locate tendon action and its prominence whilst movement, is very important. Knowledge of
the normal range of motion values, muscle strength testing methods and grading systems and
the ability of appreciating the substitution or compensatory movements is necessary.
2. A quick screening test or functional assessment or observation of the client/patient (whilst
the client/patient enters the examination room, attains different positions, during interview etc.)
may be performed prior to formal muscle strength testing procedure.
3. Manual muscle strength testing is performed by Break Test when muscle contracts
isometrically at the end range of motion or by Active Resistance Test when muscle contracts
actively isotonically from initial to end range / mid-range of motion.
4. As a general rule, range of motion, muscle length tests and joint stability evaluation precedes
manual muscle strength testing.
5. Consider clients/patients’ comfort level and respect pain if any, as priority and insist on such
privacy, as will gain the patients co-operation and undivided attention whilst the joint/part to
be tested is uncovered to the modest level. Consider cultural, social and gender issues whilst

8. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
exposing the part to be tested and whilst palpation of the muscle or group of muscles being
tested.
6. Select the appropriate environment for muscle strength testing i.e., firm examination
table/plinth, quite and non-distracting examination room with a screen for privacy, one witness
for e.g., a relative or a nurse, during the examination, optimal room temperature and ventilation
of the examination room for a partially disrobed client/patient.
7. All the materials needed for comprehensive evaluation and for manual muscle strength
testing shall be readily available and kept handy near the examination table prior to initiating
manual muscle strength testing e.g., documentation/evaluation proforma, stationary for
documentation, goniometers, pillows, towels, draping sheets, wedges or pads for positioning,
an assistant or a relative or a nurse, emergency call system if no assistance available, reference
material etc.
8. Use some method of warming up of the muscles especially in the cold, cyanotic and
weakened muscles prior to muscle strength testing.
9. Position/place the client/patient in a position that offers the best fixation/stabilization of the
body as a whole e.g., supine-lying, side-lying, prone-lying or sitting. The examiner/therapist
shall position himself/herself in relation to the client/patient for optimal evaluation i.e., on the
side to be tested.
10. Fix/stabilize the part of the body proximal to the part/joint to be tested to eliminate
extraneous/compensatory movements, isolate the muscle or muscle group, ensure the correct
test movement and eliminate substitution movements.
11. Prior to manual muscle strength testing, the examiner/therapist shall demonstrate and
describe the test movement to the client/patient.
12. Use the test movement in the horizontal plane (eliminating gravity position) whilst testing
muscles that are too weak to function against gravity. Place the part to be tested in anti / against
gravity test position whenever it is appropriate.
13. Observe the movement for possible compensatory/substitution movements and explain to
eliminate it via optimal fixation/stabilization of proximal part and check for the amount of
range of motion completed by the client/patient.
14. Palpate the muscle contractions by placing fingers over one or more of the primary muscles
and/or its tendinous insertion (also observe for tendon becoming taut) during test movement.
15. Resist/Apply Pressure: Use the palm of the hand to resist in the opposition direction of the
test movement. Apply resistance on the distal end of the moving bone. Consider the hand

9. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
position for long lever versus short lever which changes the amount of resistance that is applied
by the examiner/therapist.
For Break Test: apply resistance after the completion of the range of motion and for Active
Resistance test apply resistance throughout the range gradually allowing the client/patient to
get set and hold and apply uniform pressure/resistance avoiding localized pressure that can
cause discomfort to the client/patient.
16. Grade & Record: Record the appropriate grade of muscle strength according to the degree
of range of movement completed, the plane in which the movement was performed i.e.,
eliminating gravity or anti / against gravity plane and the amount of resistance tolerated by the
client/patient.
17. Optimal test position for a one-joint muscle is at the completion of range of motion and the
optimal test position for a two or multi-joint muscle is within the mid-range of motion of its
overall length.
18. Differentiate
a. One-joint Muscle from Two-Joint Muscle that crosses over the same joint by shortening the
two joint muscle and making it in-effective
e.g., Differentiating Soleus from Gastrocnemius for Ankle Plantarflexion
b. One-joint Muscle from Another One-Joint Muscle that crosses over the same joint on the
basis of the action that are similar and that are different
e.g., Differentiating Flexor Carpi Radialis from Flexor Carpi Ulnaris for Wrist Flexor Muscle
Strength Testing by asking the client/patient to perform wrist flexion in radial deviation or wrist
flexion in ulnar deviation respectively
c. Multi-joint Muscle from Another Multi-Joint Muscle by precise positioning of the joints to
restrict certain action
e.g., Differentiating Flexor Digitorum Superficialis from Flexor Digitorum Profundus by
optimally placing the finger metacarpophalangeal (MCP), proximal interphalangeal (PIP) and
distal interphalangeal (DIP) joints
d. Action of Different Fibres of a Multi-fibre Muscle by precise positioning and by correct
application of resistance/pressure by the examiner/therapist
e.g., Differentiating Anterior Deltoid Fibres from Posterior Deltoid Fibres by asking the
client/patient to perform shoulder flexion versus shoulder extension respectively
19. To avoid frequent re-positioning of the client/patient, follow the sequence of muscle testing
whilst performing manual muscle strength testing of the entire body or entire extremities, in

10. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
order of supine-lying (back-lying), side-lying, prone-lying (face-lying) and finally sitting
position.
20. Consider both options of muscle strength testing i.e., subjective versus objective methods
of evaluation depending upon the frame of approach, need/requirements of the client/patient,
availability of the resources, instruments, time, expertise and experience of the
examiner/therapist and treatment goals as well as institutional policies.
21. Repeated and perfect practice is must to acquire proficiency and skills in muscle strength
testing and accurately grading the muscle strength.
22. Consider or take into account, the concepts of passive insufficiency and active insufficiency
and class I, II, III and IV muscle or group of muscles, whilst muscle strength testing and grading
the muscle strength.
Passive Insufficiency
As defined by O'Connell and Gardner: Passive insufficiency of a muscle is indicated whenever
a full range of motion of any joint or joints that the muscle crosses is limited by that muscle's
length, rather than by the arrangement of ligaments or structures of the joint itself
As defined by Kendall et al.: Passive insufficiency. Shortness of a two-joint (or multi-joint)
muscle; the length of the muscle is not sufficient to permit normal elongation over both joints
simultaneously. e.g., Short Hamstrings.
Active Insufficiency
As defined by O'Connell and Gardner: If a muscle which crosses two or more joints produces
simultaneous movement at all of the joints that it crosses, it soon reaches a length at which it
can no longer generate a useful amount of force. Under these conditions, the muscle is said to
be actively insufficient. An example of such insufficiency occurs when one tries to achieve full
hip extension with maximal knee flexion. The two-joint hamstrings are incapable of shortening
sufficiently to produce a complete range of motion of both joints simultaneously
As defined by Kendall et al.: Active insufficiency. The inability of a Class III or IV two-joint
(or multi-joint) muscle to generate an effective force when placed in a fully shortened position.
The same meaning is implied by the expression "the muscle has been put on a slack”.
VI. Purposes of Muscle Strength Testing
1. To determine the amount of muscle strength available and thus establish a baseline for
planning treatment.
2. To discern how muscle weakness is limiting performance of activities of daily living (ADL).

11. First (I) BOT. 105 Introduction to Occupational Therapy and Therapeutic Activities. Section A:
Introduction to Occupational Therapy. Module VIII: Overview of Assessments: Muscle Strength.
Punita V. Solanki. July 2022
3. To prevent deformities that can result from imbalance of muscle strength between agonist
vs antagonist muscle /group of muscles, at a particular joint.
4. To determine the need for assistive devices or splinting or modified ways of performing
ADL.
5. To evaluate the effectiveness of treatment plan on follow-up evaluations after therapy
sessions.
VII. Limitations of Muscle Strength Testing
1. Muscle strength testing methods cannot measure muscle endurance (number of times the
muscle can contract or duration of muscle contraction at its maximal effort).
2. Muscle strength testing methods cannot measure co-ordination (smooth rhythmic interaction
of muscle functions).
3. Muscle strength testing methods cannot measure performance capabilities of the
client/patient i.e., use of the muscle or group of muscles in functional activities.
4. Muscle strength testing methods cannot be used accurately in clients/patients who have
muscle tone variations i.e., spasticity which is caused by upper motor neuron disorders e.g., in
cerebral palsy, cerebro-vascular accidents etc.
VIII. Home Work Assignment and For Class Discussion
1. History of manual muscle strength testing
2. Definitions and examples of class I, II, III and IV muscles/group of muscles
3. Different Manual Muscle Strength Grading Systems