Muscle Strength Testing
University of the Philippines Manila
COLLEGE OF ALLIED MEDICAL PROFESSIONS
PT 142 Assessment in Physical Therapy
Mitch B. Encabo, MPA, PTRP
Edited for instruction by:
Aila Nica J. Bandong, PTRP
LEARNING OBJECTIVES
At the end of the session the students should be
able to:
 Define muscle strength and their functional
implications
 Discuss basic considerations in performing muscle
strength testing
 Differentiate methods of doing muscle strength testing
 Discuss Daniels and Worthingham’s manual muscle testing
 Discuss modified tests used in assessing muscle strength
 Instrumental muscle strength testing
 Functional muscle strength testing
 Discuss probable conditions that require modifications
of the standard technique
MUSCLE STRENGTH TESTING
 Refers to the determination of the strength of a
muscle or muscle group
 Does not reflect muscle function
 Test based on the
 Effective performance of movement
 Manual resistance
 Gravity
MUSCLE STRENGTH TESTING
Purpose
 Diagnostic
 Examine the improvement or deterioration of a patient’s






status over time
Predictive or prognostic tool
Determine the extent of strength loss
Outcome measures in clinical research
Determine the need for compensatory measures or
assistive devices
Helps in the formulation of the treatment plan
Evaluates the effectiveness of treatment
MUSCLE STRENGTH vs ENDURANCE
Muscle Strength
Muscle Endurance
 Force production
 Repeated contractions
 Voluntary exertion in
 Maintenance of isometric
one maximal effect
 Results in isotonic or
isometric contractions
 Gross indicator of
functional ability
contraction
MUSCLE WEAKNESS
 Any reduction of the normal ability of the muscle
to generate force
 Causes:
 Muscle strain
 Pain, reflex inhibition
 PNI, Nerve root lesion, UMNL
 Tendon pathology, avulsion, rupture
 Prolonged disuse/immobilization
 Psychological overlay
Test
performance
Evaluation
of muscle
strength
TEST COMPONENTS
Test Performance
 Muscle origin, insertion and action
 Function of participating muscles
 Patterns of substitution
 Ability to detect contractile activity
 Ability to palpate muscle or tendon
 Ability to detect atrophy
 Recognize abnormal position or movement
Test Performance
 Awareness of deviation from normal ROM ,
laxity or deformities
 Identify muscles with the same innervation
 Relationship of diagnosis to sequence and extent
of test
 Ability to modify test procedures as necessary
 Effect of fatigue
 Effect of sensory loss and movement
Evaluation of Muscle Strength
 Detect substitution whenever weakness exist
 Accurate grading of muscle strength
BASIC CONSIDERATIONS
 Observation
 Palpation
 Positioning
 Stabilization
 Resistance
 Validity and reliability
Observation and Palpation
 Observe the size and contour of muscles
 Palpate contractile tissues
Positioning
 Patient comfort
 Depends partly on the effect of gravity
 Use position that offers the best fixation of the
body as a whole
 Use antigravity positions as applicable
 Two jointed muscles
Stabilization
 Proximal attachment of muscles
 Used to isolate the desired action to a specific
joint
 Stabilize the part proximal to the part being
tested
 Stabilization of the proximal attachment of the
muscle through:
 Muscle tension
 Gravitational pull
 External pressure from
manual stabilization
Resistance
 Force that acts in opposition to a contracting
muscle
 Applied in the direction opposite the line of pull
 Must never be sudden or jerky
 Applied gradually, but not to slowly, to allow the
patient to “get set and hold”
 Applied uniformly
 Long lever arm vs Short lever arm
 Break test vs Active resistance test
Break Test
Active Resistance Test
• Resistance applied
at the end range
• Patient is asked to
hold the part at a
point and examiner
“breaks it”
• Application of
manual resistance
against actively
contracting muscles
• Examiner gradually
increases resistance
until maximum
tolerance
Validity and Reliability
 Inherent limitation
 Types of muscle contractions
 Rate of tension development
 Affected by
 Difference in testing methods
 Magnitude of resistance
 Force application, point of application, speed
 Factors




Patient factors
Therapist factors
Environmental factors
Others
Validity and Reliability
 Patient Factors  Therapist factors  Environmental
 Age
 Experience
factors
 Gender
 Manner and content
 Temperature
 Pain
of instructions
 Interaction
 Distractions
 Fatigue
 Other factors
 Lower motor
 Muscle factors
neuron disease
 Spasticity
 Psychological factors
 Methodological
factors
METHODS
Manual
Functional
Instrumental
Muscle
Strength
Testing
METHODS
OF
MMT
Daniels and
Worthingham
Kendall
Motion
Individual
muscles
* Gradually increasing
* Maximum at endrange
Maximum at
midrange
Type of Contraction
Concentric to
isometric
Isometric
Method of Grading
Numerical or
qualitative scores
Percentages
What is being tested?
Resistance
Daniels and Worthingham MMT
 Criteria used in assigning a muscle grade
 Factors considered include the following:
Subjective Factors
 Examiner’s
Objective Factors
 Ability of the patient
impression of the
to move the body part
amount of resistance against gravity
to give before the
 Ability of the patient
actual examination
to complete full range
 Amount of
of motion
resistance that the  Ability of the patient
patient tolerates
to hold the position
during the actual
once at the end of the
test
range of motion
Other Factors
 Amount of manual
resistance applied
 Ability of the muscle
to move the part
through the full ROM
 Effect of gravity
 Evidence of
contraction
Daniels and Worthingham MMT: GRADING
 Normal ( N or 5 )
 Full range against maximum resistance and gravity
 Good ( G or 4 )
 Full range against moderate resistance and gravity
 “Gives” or “yields” at the end of the range given maximum resistance
 Functional threshold for the lower extremity
 Fair Plus ( F+ or 3 )
 Full range against mild resistance and gravity
 “Gives” or “yields” to some extent at the end of its range given
moderate or maximum resistance
 For users of orthosis
 Fair ( F or 3 )
 Full range against gravity
 “Gives” at the end of the range against mild resistance
 Functional threshold for the upper extremities
Daniels and Worthingham MMT: GRADING
 Poor ( P or 2 )
 Full range, gravity eliminated
 Poor Minus ( P- OR 2 - )
 Partial range gravity eliminated
 Trace ( T or 1 )
 Visible or palpable contraction
 No movement of the body part
 Zero (0)
 No visible or palpable contraction
How to Document???
All muscles of the trunk and extremities are grossly
graded 5/5 EXCEPT:
® Shoulder abductors – 3/5
® Knee flexors – 3/5
Significance: Muscle weakness 2 to deconditioning
How to Document???
 BREAK TEST
All the muscles of the wrist and hand are grossly
graded 5/5 EXCEPT:
® wrist flexors – 4/5
® radial deviators – 4/5 ( 10 deg )
Significance: Muscle weakness 2 to pain brought
about by reflex inhibition
How to Document???
 RANGE TEST
All of the muscles of the lower limb are grossly
graded as 5/5 EXCEPT for
® hip extensors = 4/5 (0-90 degrees)
® hip adductors = 4/5 (0-20 degrees)
Significance: Muscle weakness due to prolonged
immobilization, range test was used 2 to
contractures of the hip flexors and
adductors
Daniels and Worthingham MMT:
LIMITATIONS
 Presence of UMNL/ Spasticity
 Presence of joint instability due to chronic flaccidity
 Presence of severe contractures
Daniels and Worthingham MMT:
AREAS/CONDITIONS THAT REQUIRE
MODIFICATIONS
 Hands and toes
 Face
 Neck
 Weight bearing muscles
 Children
Hands and Toes
 Weight is minimal so effect of gravity is unimportant
and need not be considered
 Tested in either gravity eliminated or gravity-assisted
position
 Grading:
5
4
3
2
1
Full range with max resistance
Full range with mod resistance
Full ROM (whether gravity eliminated or assisted)
Partial ROM (whether gravity eliminated or assisted)
Palpable or observable flicker of muscle contraction
Face
 Not always practical or possible to palpate muscle,
apply resistance, or position the patient
 Grading:
 N/F (N)or light impairment
Completes test movement with ease and control
 WF Moderate impairment that affects the degree of
active motion
Performs test with difficulty
 NF Severe impairment
Minimal muscle contraction
0
Absent
Neck
 Using gravity eliminated position when testing
for neck flexion and extension is impractical
 A muscle grade of 2 is assigned when the patient
can complete partial ROM while in a gravity
resisted position
Weight Bearing Muscles
 To be resisted maximally, some muscles require
the assistance of body weight
 For gastrocnemius and soleus only
Children
 May not cooperate with standard MMT
procedures
 2-5 y/o can initiate test position, but they cannot
sustain it because they don’t understand the
concept of exerting counterforce vs examiners
resistance
 Needs to be modified for 4-6 y/o
Daniels and Worthingham:
MODIFIED TESTS
 Combined tests for the extremities
 Quickie tests
 Squatting
 Walking on heels and toes
 Break test
 Movement cannot be totally prevented but can be
minimized by telling the patient “don’t let me move you”
 Evaluation of functional activities
 Donning and doffing
 Gripping the examiners hand
Daniels and Worthingham:
CONSIDERATIONS
 Always start the test at grade 3
 In case a movement needs to be tested in the non-standard
position , indicate the position used
 When in doubt about the grade assigned to a muscle group
place a (?) beside the grade
 Note special cases ( MMT of fingers or toes, UMNL )
 Freedom from discomfort or pain
 Quiet non-distracting well ventilated environment
 Adequately firm and wide plinth with adjustable height
 Minimal position changes
 Presence of all materials needed for the test
Instrumented Muscle Testing
 Advantage: increases the level of accuracy and
reliability of strength testing
 Instruments/ devices
 Cable tensiometer
 Strain gauge
 Hand-held dynamometer
 Modified sphygmomanometer
 Grip strength dynamometer
 Pinch meter
Cable Tensiometer
Strain Gauge
Hand-held Dynamometer
Modified Sphygmomanometer
Pinch Meter
Instrumented Muscle Testing:
LIMITATIONS
 Measures isometric strength only
 Not useful for testing trunk strength
Instrumented Muscle Testing:
CONSIDERATIONS
 Reliability is reasonable
 Important to standardize strength
 Instruments are not interchangeable
Dynamic Muscle Testing
 Makes more sense since muscles function dynamically
 Machine use: Isokinetic machines
Isokinetic Testing Machine:
LIMITATIONS
 Validity has not yet been established
 Movement occurring at constant speed is artificial
 Positions and movement constraints are not
realistic
Functional Muscle Testing
 Utilized in cases when muscle strength cannot be
tested by MMT:
 Presence of spasticity and flaccidity
 Patients with poor comprehension
 Patients who are unable to follow instructions
 Observations and description of certain
movements or activities of the patient
REFERENCES
Clarkson & Gilewich(1989), Musculoskeletal Assessment. Joint Range of Motion
and Manual Muscle Strength: Williams & Wilkins.
Erickson and McPhee(1993) Clinical Evaluation. In Delisa: Rehabilitation
Principles and Practice (2nd ed). Philadelphia: JB Lippincott Company.
Harms - Ringdahl(1993)International Perspectives in Physical Therapy.Muscle
Strength. New York: Churchill Livingstone.
Hislop and Montgomery(2002): Daniels and Worthingham’s Muscle Testing:
Techniques of Manual Examination(7th ed) Philadelphia:WB Saunders
Company.
Kendall,McCreary, Provance: Muscle Testing and Function (4th ed)Baltimore:
Williams and Wilkins, 1993.
Magee(1997) Orthopedic Physical Assessment(3rd ed) Philadelphia: WB
Saunders Company.
Tobis and Hong (1990) Muscle Testing in Kottke and Lehmann: Krusen’s
Handbook of Physical Medicine and Rehabilitation (4th Ed) Philadelphia:WB
Saunders Company