This study aimed to determine the intrarater reliability of manual muscle testing (MMT) and hand-held dynametric muscle testing (DMT) by having a physical therapist perform both types of tests on the same muscle groups for 11 patients on two separate occasions. The results found high correlation coefficients between tests for most muscle groups with both MMT and DMT, indicating that both methods demonstrate reliability under the conditions of this study. However, some limitations exist for each testing method.

1. Intrarater Reliability of Manual Muscle Testing and
Hand-held Dynametric Muscle Testing
CAROLYN T. WADSWORTH,
RUTH KRISHNAN,
MARY SEAR,
JEAN HARROLD,
and DAVID H. NIELSEN
Physical therapists require an accurate, reliable method for measuring muscle
strength. They often use manual muscle testing or hand-held dynametric muscle
testing (DMT), but few studies document the reliability of MMT or compare the
reliability of the two types of testing. We designed this study to determine the
intrarater reliability of MMT and DMT. A physical therapist performed manual and
dynametric strength tests of the same five muscle groups on 11 patients and
then repeated the tests two days later. The correlation coefficients were high
and significantly different from zero for four muscle groups tested dynametrically
and for two muscle groups tested manually. The test-retest reliability coefficients
for two muscle groups tested manually could not be calculated because the
values between subjects were identical. We concluded that both MMT and DMT
are reliable testing methods, given the conditions described in this study. Both
testing methods have specific applications and limitations, which we discuss.
Key Words: Muscle contraction, Muscle performance, Physical therapy.
Muscle strength assessment is an in- obtaining these measurements has not potential for human error. Up to 40%
tegral aspect of physical examination. been ascertained. of the body's muscles, however, are so
Knowledge of muscle strength, that is, Manual muscle testing is the most small that the part of the grading sys-
the muscle's ability to produce tension, widely used clinical method of strength tem based on gravity resistance is in-
assists an examiner in making a differ- assessment.1 Manual muscle testing is applicable.3,6,7
ential diagnosis, measuring improve- based on a system of grading movement Iddings et al, in one of the few pub-
ment or deterioration, determining against examiner or gravity resistance, lished studies that address the reliability
functional impairment, and planning first used by Lovett in 1912.2,3 Several of MMT, found that MMT used in a
therapeutic measures. Physical thera- aspects of this system have led to its clinical setting can be highly reliable
pists have contributed to the develop- being classified as a semiquantitative despite differences in examiner training
ment of muscle strength assessment method of measurement. Some of the and testing techniques.8 Other research-
methodologies and routinely use them MMT grades rely largely on an exam- ers, who appraised MMT for standardi-
on a frequent basis. Not all methodol- iner's judgment. For example, an ex- zation in the poliomyelitis vaccine trials,
ogies, however, yield equally quanti- aminer's subjective assessment of the also found it to be reliable.9,10 In con-
fiable results. The need for accurate, amount of resistance applied is inherent trast, Beasley found that physical thera-
reliable strength measurements is un- in the grading criteria for strengths in pists using MMT were unable to identify
deniable, but the best method for the Good to Normal range.4-7 In con- up to 50% of loss of knee extensor mus-
trast, the grading criteria for muscle cle strength in patients with poliomye-
strengths in the Poor to Fair range are litis.11 In this study, physical therapists
Mrs. Wadsworth is Lecturer, Physical Therapy more objective because an examiner assigned Normal grades to muscles that
Education, College of Medicine, The University of uses gravity as a standard. Another sub- were able to produce up to only half the
Iowa, 2600 Steindler Bldg, Iowa City, IA 52242
(USA).
jective aspect of MMT is that an exam- force on a cable tensiometer of age-
Ms. Krishnan is Staff Physical Therapist, Moline iner must develop an internal basis for matched norms.11 Also, therapists using
General Hospital, Moline, IL 61265. comparing test results, for example, MMT did not distinguish muscle
Ms. Sear is Instructor in Physical Therapy, Uni-
versity of Kansas, Kansas City, KS 66103.
being able to sense normative values for strength differences of 20% to 25% be-
Ms. Harrold is Staff Physical Therapist, Marian age, sex, or size of body parts. An ex- tween patients' strong and weak sides.11
Health Center, Sioux City, IA 51101. aminer also relies on personal experi- More studies are needed to substantiate
Ms. Krishnan, Ms. Sear, and Ms. Harrold were
students in the physical therapy program, The Uni- ence and skill to palpate muscles and one or the other contradictory conclu-
versity of Iowa, at the time this study was con- tendons, detect substitution, and prop- sion of these studies.
ducted. erly stabilize the patient for MMT. Use
Dr. Nielsen is Associate Professor, Physical Ther-
An alternative to MMT is a quanti-
apy Education, College of Medicine, The University of the standardized MMT protocol, tative, instrumented system for assessing
of Iowa. which specifies test positions and incor- muscle strength. The Graham-Desagu-
This article was submitted May 2, 1986; was with
the authors for revision 15 weeks; and was accepted
porates gravity as at least one objective liers force dynamometer, developed in
November 3, 1986. Potential Conflict of Interest; 4. measurement criterion, helps reduce the London in 1763 to measure human
1342 PHYSICAL THERAPY

2. RESEARCH
muscle strength while eliminating syn- need to identify a reliable, clinically ac- 1. Wrist extensors—tested with the sub-
ergistic activity, was the earliest reported ceptable method of muscle strength as- ject seated in a chair with his forearm
instrumented system.12 In 1798, Regnier sessment, we designed our study to de- supported on an adjacent bed, but
in Paris invented an all-purpose portable termine the intrarater reliability of with his hand unsupported. The sub-
dynamometer, which he used for the MMT and DMT, including subjective ject's elbow was flexed to 90 degrees,
first recorded attempt to study muscle between-method comparisons of relia- his forearm was pronated, his wrist
strength in individuals with diseases.12 bility. We also examined the advan- was extended to 30 degrees, and his
Numerous devices have been designed tages, disadvantages, and clinical utility fingers were relaxed. The rater stabi-
since to provide objective, quantitative of these two methods. We expected both lized the subject's forearm on the bed
strength measurements. They register methods to be reliable because of their and resisted movement through con-
the peak force generated by a muscle widespread clinical acceptance; how- tact over the dorsum of the sub-
through loading in tension or compres- ever, we hoped this investigation would ject's hand.
sion. provide more information regarding the 2. Shoulder abductors—tested with the
Myometers, cable tensiometers, dy- discriminating capabilities of each. subject seated in a chair with his
namometers, and grip meters all have shoulder abducted to 90 degrees, in
been shown to be statistically reliable METHOD zero degrees of rotation, and with his
instruments for testing muscle strength elbow extended. The rater stabilized
under various conditions.4,5,13-19 For ex- Subjects the subject's shoulder girdle with one
ample, Mathiowetz et al, who studied The human subjects committees of hand just proximal to the glenohu-
grip and pinch strength using hand- The University of Iowa and St. Luke's meral joint and resisted movement
held grip dynamometers and pinch Hospital, Cedar Rapids, Iowa, approved through contact over the distal end
gauges, found interrater correlation this study before subject screening. Cri- of the humerus.
coefficients to be .97 or above and test- teria for subject selection included a 3. Hip flexors—tested with the subject
retest reliability coefficients .80 or minimum of Fair strength (able to as- seated in a chair with his back sup-
above; they emphasize that raters must sume and hold test positions against ported and his pelvis stabilized by
follow standardized test procedures to gravity) in the muscle groups to be the chair; the subject's arms were
obtain these results.18 In a comparison tested, no spasticity, and the ability to across his chest, and his hip was
of a cable tensiometer, a Wakim-Porter isolate movements on command. We flexed to 135 degrees. The rater re-
strain gauge, a spring scale, and a selected 13 subjects who met the criteria sisted movement through contact
Neuman myometer, Clarke found the and consented to participate in the study over the distal end of the femur.
tensiometer to be the most precise in- from inpatients receiving physical ther- 4. Elbow extensors—tested with the
strument with a test-retest interrater cor- apy at St. Luke's Hospital. We per- subject lying supine on a bed with
relation coefficient greater than .90.13 formed initial tests on all 13 subjects, his shoulder flexed to 90 degrees, in
In the sparse literature comparing the but because of circumstances unrelated zero degrees of rotation, and his el-
results obtained through MMT and to their disorders, two subjects could not bow flexed to 45 degrees. The rater
muscle testing with a hand-held force- participate in the retest session. The sub- stabilized the subject's upper arm
measuring device, one study measured jects had various chronic orthopedic and resisted movement through con-
the hip flexor and abductor muscle and neuromuscular diagnoses, produc- tact over the distal end of the ulna.
strength of 128 patients with unilateral ing muscle strength deficiencies that es- 5. Kneeflexors—testedwith the subject
lower extremity pathological conditions. sentially were stable. Their mean age lying prone on a bed with his hip in
An examiner using a hand-held device was 70 years, with a range of 21 to a neutral position and his pelvis sta-
was able to detect consistently unilateral 96 years. bilized by the bed; the subject's knee
weakness as identified by another ex- was flexed to 75 degrees. The rater
aminer using MMT.1 A similar study Procedure stabilized the subject's thigh against
compared the data obtained from bilat- the bed and resisted movement
erally testing hip flexors and abductors We used a test-retest design in which through contact over the distal end
with a hand-held device to the same one rater performed duplicate tests of his tibia.
tester's subjective identification of the (MMT and DMT) offivemuscle groups The testing position needed to be
stronger limb. The tester's subjective as- on the same patients, then repeated the modified for two subjects who could not
sessment was correct in 82% of the tests two days later. We randomized the tolerate or assume the standard posi-
cases, but he was unable to identify the type of testing and the order of the mus- tions. One subject was positioned prone
stronger limb when the mean strength cle groups. A physical therapist with to test the elbow extensors, and the other
difference between limbs was less than eight years of clinical experience served was positioned side lying to test the knee
8.8% in abduction and less than 6.4% as the rater. She performed all tests on flexors. These modifications did not ap-
in flexion.20 the patients' involved (potentially weak- pear to hinder the rater.
Few, if any, studies have determined ened) limbs. We examined five muscle We used the following protocol
the intrarater reliability of both MMT groups, selected for their ease of meas- throughout testing. An investigator
and hand-held dynametric muscle test- urement, that is, muscle groups with screened a subject's chart for pertinent
ing (DMT) to compare the two modes testing positions that could be assumed information and identified the side of
of testing. Most physical therapists as- readily by the patients and reproduced the involved limbs that were to be tested.
sess muscle strength using one or both accurately and maintained by the ther- Just before testing, one investigator,
methods. A reliability study would facil- apist. These muscle groups and their serving as a subject liaison, met with the
itate their choice of method and confi- standardized testing positions are the subject to explain the procedure and
dence in their results. Recognizing the following2,3: answer questions. She requested that the
Volume 67 / Number 9, September 1987 1343

3. subject not converse with the rater in an
attempt to eliminate bias regarding the
subject's status. She then prepared the
subject for testing. The rater entered the
room and began testing. Another inves-
tigator, serving as a recorder, directed
the rater according to the preestablished,
randomized mode and order of testing.
She told the rater which side to test,
which mode of testing to administer
first, and the order in which to test the
muscle groups. She also recorded all
results, verbalized by the rater, and com-
puted the torque measurements ob-
tained with the dynamometer.
The rater performed MMT using the
positions previously described. She used
a "break test," in which a subject ac-
tively holds a body part in a prescribed
position, while an examiner attempts to
"break" the hold by a manual counter-
force (Fig. 1). The rater consistently
commanded the subject to "hold, hold,
don't let me move you" during the con-
traction, which lasted about five sec-
onds.
The rater used the MMT grading Fig. 1. Testing kneeflexormuscles using manual muscle testing.
system, described by Daniels and
Worthingham2 and Kendall and Mc-
3 = Poor minus: The ability to move
Creary.3 We assigned ordinal values to
the body part more than half way
the respective descriptive classification
to completion of the test position
levels for the purpose of statistical analy-
with gravity lessened.
sis as follows:
11 = Normal: The ability to move the 2 = Trace plus: The ability to move the
body part into the test position and body part less than half way to
hold against gravity and maximum completion of the test position
resistance. with gravity lessened.
10 = Good: The ability to move the 1 = Trace: The ability to initiate a fee-
body part into the test position and ble contraction or flicker of muscle
hold against gravity and moderate or tendon movement that is visible
resistance. or palpable, but does not move the
9 = Good minus: The ability to move body part.
the body part into the test position Fig. 2. Hand-held dynamometer and tape
0 = Zero: No ability to contract the
and hold against gravity and some muscle. measure used in dynametric muscle testing.
resistance.
8 = Fair plus: The ability to move the The rater used a calibrated 25-kg Cha- measured the distance from the center
body part into the test position and tillon* hand-held dynamometer for of the dynamometer pad to the joint
hold against gravity and minimum DMT (Fig. 2). She chose a cuff of ap- axis. The recorder documented each
propriate size to fit a subject's limb. She force measurement and calculated the
resistance.
held the dynamometer perpendicular to torques as the products of the distance
7 = Fair: The ability to move the body the limb at the specified contact points. and the forces.
part into the test position and hold She tested the subjects in the positions The subject liaison investigator re-
against gravity. previously described for MMT. She used mained with the subject to answer any
6 = Fair minus: The ability to move
the body part more than half way a "make test," in which a subject exerts questions after testing. The same pro-
to completion of the test position maximum force against the stationary cedure was followed during the retest,
against gravity. dynamometer (Fig. 3). She used the ver- which was conducted two days later.
bal command "Push, push. Is that all
5 = Poor plus: The ability to move the
you've got?" during the contraction, Data Analysis
body part less than half way to
which lasted about five seconds. The
completion of the test position A simple computer procedure was
rater performed three trials and then
against gravity. used to rank the MMT ordinal data in
4 = Poor: The ability to move the body ascending order (from lowest to highest)
part into the test position with * John Chatillon & Sons, 83-30 Kew Gardens before the statistical analysis. The statis-
gravity lessened. Rd, Kew Gardens, NY 11415. tical analysis involved computing be-
1344 PHYSICAL THERAPY

4. RESEARCH
ferences during DMT for the other mus-
cle groups.
DISCUSSION
As reflected by the between-test cor-
relation coefficients and lack of signifi-
cant mean differences, MMT for shoul-
der abduction, hip flexion, and knee
flexion demonstrated good intrarater re-
liability in this study. These results com-
plement the findings of Iddings et al8
and Lilienfeld et al,10 which showed that
MMT had high interrater reliability.
These results, therefore, suggest that
MMT is a consistent evaluation tool.
Our results, however, also reflect that
MMT is less discriminating than DMT
in identifying small differences in mus-
cle strength. Because we adhered to the
MMT grading system with inherently
few increments, MMT was less sensitive
than DMT to variability in strength of
muscles in the Fair to Normal range.
Beasley also identified this limitation of
Fig. 3. Testing knee flexor muscles using dynametric muscle testing. MMT.11 Thus, physical therapists can
use MMT with confidence in its relia-
TABLE bility, but may not be able to detect
Test-Retest Reliability Coefficients muscle strength increments as discretely
Dynametric
as with instrumented systems.
Manual Muscle Dynametric muscle testing also dem-
Muscle
Muscle Groups Testing onstrated high intrarater correlation
Testing
(r) (r) coefficients. In contrast to the almost
Wrist extensors a
.88b
identical test-retest mean MMT values,
Shoulder abductors .98b
.69 the retest mean DMT values were higher
Hip flexors .74b .72* for all five muscle groups, with two tests
Elbow extensors a
.90* being statistically significant. We attrib-
Knee flexors .63 .75* uted the observed increases to a learning
a effect, which could be minimized by
Ellipsis indicates that reliability coefficient could not be calculated for this muscle test
because the MMT grade was essentially the same for all subjects for the test-retest data. With
familiarizing subjects with the dyna-
the exception of one subject who had an MMT grade of 10 on one test and a grade of 11 on mometer during a practice session. (Per-
the other test, all subjects demonstrated the grade of 11 for both tests. haps further study is indicated to deter-
* Statistically significant from zero (p < .05). mine the amount of practice needed
before stabilizing of values.) Our results,
tween-test Pearson product-moment re- elbow extensor muscles because, with thus, support physical therapists' use of
liability coefficients and between-test the exception of one subject, the subjects a hand-held dynamometer as a reliable
Student's paired t tests on the DMT and demonstrated a grade of 11 on both the muscle strength testing tool.
ranks of the MMT data. Pearson prod- test and retest, invalidating this statisti- Manual muscle testing and DMT
uct-moment correlation analysis and cal technique. The test-retest reliability were comparably reliable, given the con-
Student's t tests on the ranks of the coefficients for the DMT ranged from ditions described in this study, but each
ordinal data are equivalent to Spear- .69 to .90. With the exception of the method has specific applications and
man's rank order correlation analysis shoulder abductor muscles, the test-re- limitations. Manual muscle testing is
and the Wilcoxon matched-pairs signed- test reliability coefficients for all muscle clinically versatile and inexpensive to
ranked test, respectively.21 groups during DMT were statistically administer, requiring only an appropri-
significant (p < .05). ate supportive base for a subject. This
RESULTS The paired t test revealed that no sig- system is devised to measure the entire
nificant test-retest mean differences oc- range of muscle strength from Zero to
As shown in the Table, the test-retest curred during MMT for all muscle Normal, but is limited to only 12 ordinal
reliability coefficients for the MMT groups (p > .05) (Fig. 4). The paired t values that produce an inherent limita-
ranged from .63 to .98 and were statis- test, however, did demonstrate signifi- tion in measurement resolution. Using
tically significant (p < .05) for the shoul- cant test-retest mean differences during this system, a tester can grade only clin-
der abductor and hip flexor muscles. DMT for the wrist extensor and elbow ically detectable weakness and thus may
The correlation coefficients could not extensor muscles (p < .05) (Fig. 5). We not be able to discriminate accurately
be calculated for the wrist extensor and found no significant test-retest mean dif- small variations of strength, particularly
Volume 67 / Number 9, September 1987 1345

5. in the Good to Normal range. Deviation
from standardized testing procedures Test
and the subjectivity of the grading sys- Retest
tem are potential sources of error.
Muscle testing with a hand-held dy-
namometer provides a more objective
means of muscle strength measurement
than MMT with a continuous range of
torque values. Use of an instrument,
however, adds to the cost and complex-
ity of testing. This method is most useful
for measuring muscle strength greater
than Fair, although some clinicians use
it in gravity-eliminated positions.22 It is
inapplicable for measuring muscle
strength less than Poor. Use of a hand-
held dynamometer also is limited in the
upper muscle strength ranges where an
examiner may have difficulty stabilizing
the instrument and resisting the subject.
An examiner's own strength may affect Fig. 4. Manual muscle testing: test-retest mean grades and standard errors (N = 11). Al-
his ability to use a dynamometer appro- though grades 1 through 11 were possible, because of criteria for subject selection, only grades
priately with stronger subjects. 9 through 11 were present in subjects. None of the test-retest mean differences were statistically
Recommendations for further studies significant (p > .05).
include recognizing the numerous vari-
ables that can affect the reliability of
both manual and dynametric methods.
Maximal muscle contraction is limited Test
ultimately by structural properties, Retest
neural activation, and feedback mecha-
nisms.23,24 Numerous external factors
also affect a subject's ability to exert a
maximal contraction, such as pain, mo-
tivation, cooperation, limb and body
position, physical condition, feedback of
results, instructions, competition, fear,
and incentives.7,17,18,23,25 McGarvey et al
even found a statistically significant
change in isometric strength with time
of day, ranging from 3.97% to 7.22%
for different muscle groups.17
An examiner's technique, which var-
ies according to training, experience,
strength, and standards, also may influ-
ence the results of muscle strength meas-
urements.5-8,25 Other factors that must
Fig. 5. Dynametric muscle testing: test-retest mean torques and standard errors (N = 11).
be considered during muscle strength Note: Asterisks indicate statistically significant test-retest mean differences (p < .05).
testing include the type and velocity of
contraction, warm-up activity, and ad-
equate stabilization.24 Kroll proposed jects must have at least a Fair grade for days. We also minimized rater contact
that the timing of trials may introduce all muscle groups tested placed a limi- with the subjects by having different
experimental error; inadequate recuper- tation on the range of strength of the persons screen the subjects and record
ation time between trials may cause en- subjects. This limitation decreased the the test values.
ergy depletion with apparent strength variance and made assessment of relia-
decrease, whereas successive daily bility more difficult. We propose ex- CONCLUSIONS
sessions may produce a training or tending this investigation to include This study explored two common
learning effect with apparent strength in- more subjects and expanding the criteria methods of assessing muscle strength,
crease.14-16 Body position and joint an- for subject selection to allow a greater MMT and DMT. Given the restrictions
gles have been shown to be major vari- variance in strength. described in this study, we consider both
ables in muscle strength assessment, The potential for rater bias carrying methods of strength testing to be reliable
thus advancing the use of standardized over from the initial test to the retest for the muscle groups we tested. We also
test positions.5,26 exists in a study such as ours. We at- identified limitations of each method,
This study was based on a relatively tempted to minimize this bias by sepa- noting that particularly in stronger sub-
small sample. The criterion that all sub- rating the test and retest sessions by two jects the dynamometer becomes more
1346 PHYSICAL THERAPY

6. RESEARCH
5. Clarke HH, Elkins EC, Wakim KG: Relationship 16. Kroll W: Reliability of a selected measure of
difficult to stabilize and MMT becomes between body position and the application of human strength. Research Quarterly 33:410-
less discriminating. With confidence in muscle power to movements of the joints. Arch 417, 1962
both methods, we recommend allowing Phys Med 31:81-89, 1950 17. McGarvey SR, Morrey BF, Askew U , et al:
the subject's physical condition and the 6. Hosking GP, Bhat US, Dubowitz V, et al: Meas- Reliability of isometric strength testing: Tem-
urements of muscle strength and performance poral factors and strength variation. Clin Or-
clinical or laboratory setting's test objec- in children with normal and diseased muscle. thop 185:301-306, 1984
tives to determine the test of choice. Our Arch Dis Child 51:957-963, 1976 18. Mathiowetz V, Weber K, Volland G, et al: Re-
results support the reliability of testing 7. Wakim KG, Gersten JW, Elkins EC, et al: Ob- liability and validity of grip and pinch strength
jective recording of muscle strength. Arch Phys evaluations. J Hand Surg [Am] 9:222-226,
methods that physical therapists com- 1984
Med 31:90-99, 1950
monly use and thus contribute to the 19. Wiles CM, Kami Y: The measurement of mus-
8. Iddings DM, Smith LK, Spencer WA: Muscle
significance of the MMT and DMT testing: Part 2. Reliability in clinical use. Phys cle strength in patients with peripheral neuro-
methods. Ther Rev 41:249-256, 1961 muscular disorders. J Neurol Neurosurg Psy-
chiatry 46:1006-1013, 1983
9. Gonnella C, Harmon G, Jacobs M: The role of
the physical therapist in the gamma globulin 20. Saraniti AJ, Gleim GW, Melvin M, et al: The
Acknowledgments. We thank the poliomyelitis prevention study. Phys Ther Rev relationship between subjective and objective
rater, Phyllis Griffin, LPT, and John 33:337-345, 1953 measures of strength. Journal of Orthopaedic
and Sports Physical Therapy 2:15-19, 1980
Wadsworth, MA, LPT, Director of 10. Lilienfeld AM, Jacobs M, Willis M: A study of
21. Conover WJ, Iman RL: Rank transformations
Physical Therapy, both of Saint Luke's the reproducibility of muscle testing and certain
as a bridge between parametric and nonpara-
other aspects of muscle scoring. Phys Ther
Hospital, Cedar Rapids, IA, for their Rev 34:279-289, 1954
metric statistics. The American Statistician
35(3):124-132, 1981
assistance in the completion of this 11. Beasley WC: Influence of method on estimates 22. Darcus HD: A strain-gauge dynamometer for
study. of normal knee extensor force among normal measuring the strength of muscle contraction
and postpolio children. Phys Ther Rev 36:21- and for re-educating muscles. Annals of Phys-
41,1956 ical Medicine 1:163-176, 1952
REFERENCES
12. Peam J: Two early dynamometers: An histori- 23. Kroemer KHE, Marras WS: Towards an objec-
1. Marino M, Nicholas JA, Gleim GW, et al: The cal account of the earliest measurements to tive assessment of the "maximal voluntary con-
efficacy of manual assessment of muscle study human muscular strength. J Neurosci traction" in routine muscle strength measure-
strength using a new device. Am J Sports Med 37:127-134, 1978 ments. Eur J Appl Physiol 45:1-9, 1980
10:360-364,1982 13. Clarke H: Muscular Strength and Endurance in 24. Smidt GL, Rogers MW: Factors contributing to
2. Daniels L, Worthingham C: Muscle Testing: Man. Englewood Cliffs, NJ, Prentice-Hall Inc. the regulation and clinical assessment of mus-
Techniques of Manual Examination, ed 4. Phil- 1966, pp 10-16 cular strength. Phys Ther 62:1283-1290, 1982
adelphia, PA, W B Saunders Co, 1980
3. Kendall FP, McCreary EK: Muscles: Testing 14. Kroll W: Reliability variations of strength in test- 25. Edwards RHT, McDonnell M: Hand-held dy-
and Function, ed 3. Baltimore, MD, Williams & retest situations. Research Quarterly 34:50- namometer for evaluating voluntary-muscle
Wilkins, 1983 55, 1963 function. Lancet 2:757-758, 1974
4. Borden R, Colachis SC: Quantitative measure- 15. Kroll W: A reliable method of assessing iso- 26. Elkins EC, Leden UM, Wakim KG: Objective
ment of the Good and Normal ranges in muscle metric strength. Research Quarterly 34:350- recording of the strength of normal muscles.
testing. Phys Ther 48:839-843, 1968 355, 1963 Arch Phys Med 32:639-647, 1951
Volume 67 / Number 9, September 1987 1347