51Japanese Journal of Comprehensive Rehabilitation Science (2017)

Original Article

MMT measurements are acceptable in routine clinical practice:
Results from periodic medical examinations of polio survivors
Koshiro Sawada, MD, PhD,1 Eiichi Saitoh, MD, PhD,2 Motoyuki Horii, MD, PhD,1Daisuke Imoto,1 Norihide Itoh, PhD,1 Yasuo Mikami, MD, PhD,1 Takumi Ikeda, MD, PhD,1Suzuyo Ohashi, MD, PhD,1 Ryu Terauchi, MD, PhD,3 Hiroyoshi Fujiwara, MD, PhD,3Toshikazu Kubo, MD, PhD1, 3
Department of Rehabilitation Medicine, Graduate School of Medical Science, Kyoto Prefectural University ofMedicine, Kyoto, Japan2
Department of Rehabilitation Medicine I, School of Medicine, Fujita Health University, Aichi, Japan3
Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine,Kyoto, Japan1

ABSTRACT
Sawada K, Saitoh E, Horii M, Imoto D, Itoh N,Mikami Y, Ikeda T, Ohashi S, Terauchi R, Fujiwara H,Kubo T. MMT measurements are acceptable in routine
clinical practice: Results from periodic medicalexaminations of polio survivors. Jpn J Compr Rehabil
Sci 2017; 8: 51-55.
Purpose: The aim of this study was to investigate
whether manual muscle test (MMT) for the hip(abduction, flexion, and extension), knee (flexion andextension), and ankle (dorsal flexion) muscles are
acceptable in routine clinical practice.
Methods: The study included 222 participants (487examinations, 974 legs) of periodic medical
examinations for polio survivors in the Tokai districtof Japan. The subjects were 175 men (350 legs) and
312 women (624 legs) with an average age at the timeof examination of 62.2 (32-82) and 61.6 (47-83)
years, respectively. The results of handheld dynametricmuscle test were compared for each MMT grade andjoint motion.
Results: Significant differences in muscle strength
were observed for the majority of pairs of MMTgrades, excluding the MMT 0/1 pair. The specificcombinations with no significant differences wereCorrespondence: Motoyuki Horii, MD, PhD
Department of Rehabilitation Medicine, Graduate Schoolof Medical Science, Kyoto Prefectural University ofMedicine, Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku,
Kyoto 602-8566, Japan.
E-mail: horii@koto.kpu-m.ac.jp
Accepted: February 23, 2017.
The authors have no conflict of interest directly relevant tothe content of this article.
©Kaifukuki Rehabilitation Ward Association 2017
doi.org/10.11336/jjcrs.8.51

MMT 1/2 for knee flexion (women); and MMT 0/2(both men and women), 1/2 (both men and women),and 3/4 (men) for ankle dorsal flexion.
Conclusion: Clinical MMT measurements seem to begenerally acceptable, at least when performed byphysical therapists with 5 or more years of clinicalexperience. However, ankle dorsal flexion requires
especially careful assessment.
Key words: manual muscle test, dynametric muscle
test, polio, post-polio syndrome
Introduction
Although manual muscle test (MMT) is usedinternationally and its clinical usefulness is generally
recognized [1], susceptibility to tester bias has beensuggested [2, 3]. Handheld dynametric muscle test(DMT) is regarded as a more objective method [2, 3]
based on its high intra- and intertester reliability [1, 4].
Although DMT was successfully utilized for detecting
chronological changes of muscle strength in former
polio subjects with post-polio syndrome (PPS) [5],when used alone it is not suitable for detecting theexistence and/or determining the extent of muscle
strength impairment because of large individual
variations even in healthy subjects [6, 7]. Hislop et al.
pointed out the necessity of assessing the interrelation
between MMT results and muscle force measurements
obtained by using devices such as the handheld
dynamometer [8].
Historically, MMT has been widely used toevaluate muscle weakening related to poliomyelitis[9, 10]. Although the introduction of the polio vaccine
has prevented new-onset poliomyelitis cases, thepandemic outbreak of the disease that took place in
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Sawada K et al.: MMT measurements in clinical practiceJapan from the 1950s to the 1960s has created theproblem of PPS among former polio patients. The
most common symptoms include slowly progressing
muscle weakness, fatigue (both generalized andmuscular), and a gradual decrease in the size ofmuscles (muscle atrophy) [11]. Patients may sufferfrom asymmetric flaccid paralysis of variable severity
and localization (upper or lower limbs, proximal ordistal) regardless of the presence of previous
symptoms. Although spasticity does not interfere withthe testing, the lack of suitable control might make it
difficult to assess muscle weakness with MMT,
especially for grades 4 (good) and 5 (normal).
We provide a periodic medical examination as partof the comprehensive rehabilitation programs forpolio survivors who mainly live in the Tokai district ofJapan, which constitutes about 10% of Japan’s total
population. This periodic examination, which includes
MMT and DMT, is undergone by a large number ofpatients with varying degrees of motion impairment ineach affected joint. Since a number of examiners areinvolved in the testing and the examinations are to
be carried out within a limited time, the testing
environment can be considered very close to a clinicalenvironment.
The purpose of this study was to investigate whether
MMT for the hip (abduction, flexion, and extension),knee (flexion and extension), and ankle (plantarflexion) muscles are acceptable in routine clinicalpractice. Ankle plantar flexion was excluded from thisstudy because the MMT grade was affected by thelevel of muscle endurance.
Methods
1. Subjects
The periodic medical examinations for polio
survivors have been carried out every 4 months sinceJune 2007. A total of 222 patients participated in thisstudy. Among these patients, 69, 43, 108, and 2
individuals took the examination 1, 2, 3, and 4 times,
respectively, resulting in 487 examinations (974 legs)
performed between June 2007 and February 2014. Of
these, 175 examinations were performed in men (350legs) and 312 in women (624 legs). The interval
between examinations for each individual was at least
2 years. The average age at the time of examination
was 62.2 (32-82) years for men and 61.6 (47-83)
years for women. Mean height and weight were 161.9(143.0-176.9) cm and 64.1 (38.0-121.7) kg for men
and 149.8 (129.7-166.6) cm and 50.8 (29.9-80.0) kg
for women.
2. Strength assessments
Assessments were focused on the hip (flexion,extension, abduction), knee (flexion, extension), andankle (dorsal flexion) muscles on both sides.
Examinations were performed by physical therapists
Jpn J Compr Rehabil Sci Vol 8, 2017with at least 5 years of clinical experience. Several
pairs consisting of an examiner and a recorderconducted the strength assessments at each periodic
medical examination. Participants were randomly
allocated to an examiner, who performed a series of
MMT and DMT evaluations. Hip flexion was tested
first, followed in order by hip flexion, hip extension,
hip abduction, knee flexion, knee extension, and ankle
dorsal flexion.
For each joint motion, the examiner performed
MMT according to the published procedures [8], andthe strength of each muscle was graded on a scalefrom 0 to 5. Next, DMT was performed twice for eachjoint motion using a handheld dynamometer (μTasF-1®, Anima Corp., Japan) as a quantitative muscle
strength measurement. The approach of Bohannon
was followed with respect to the subject positions anddynamometer placement [12]. Isometric forces (N)determined during the first and second measurements
were recorded as F1 and F2, respectively. The greaterof the two was defined as Fmax and the remaining one
as Fmin.
The examiners were not given any information
about the participants, such as the results of previous
examinations or their clinical history throughout theassessment. Ethical approval was obtained from theethics committee of Fujita Health University.
3. Data analysis
First, correlations (Pearson product-momentcorrelation coefficient) between F1 and F2 wereinvestigated for each joint motion to evaluate if theDMT measurements were stable. The Fmax values
grouped according to the corresponding MMT grades
were then compared for each joint motion using oneway analysis of variance (one-way ANOVA) separately
for men and women, with comparisons between
individual groups conducted using the Student’s t-test
with Bonferroni correction. For the evaluation of ankle
dorsal flexion, the joints with equinus contracture(dorsiflexion of ≤ −20°) were excluded.
p values of <0.05 were considered to indicate astatistically significant difference. Statistical analyses
were conducted with StatFlex Ver. 6.0 (Artech Co.,Ltd., Osaka, Japan).
Results
1. Correlations between the first and second DMT
measurements
The relationship between F1 and F2 for eachjoint motion is shown in Figure 1. Although all thecorrelations were statistically significant, the correlation
coefficient was relatively low for ankle dorsal flexion(r = 0.616). For this motion, cases with Fmin of 0 N andFmax of ≥50 N were present in 105 of the 307 joints(34.2%).
The F1/F2 average (N) was 74.5/73.8, 73.7/74.6,

Sawada K et al.: MMT measurements in clinical practice53

Figure 1. Correlations between F1 and F2 (N) for each joint motion.
79.5/79.9, 55.1/55.5, 85.6/87.4, and 71.9/71.6 for hipflexion, hip extension, hip abduction, knee flexion,knee extension, and ankle dorsal flexion, respectively.
No statistically significant differences were detected
between F1 and F2 for any of these joint motions.
2. Relationship between MMT grades andquantitative muscle strength measurements
obtained with DMT
The averages values and SDs of Fmax according tojoint motion and gender are shown in Table 1. The
table also presents the number of joints for each
MMT grade. One-way ANOVA revealed significant
differences for every joint motion for both men andwomen (p = 0.0000). There were no significant
differences between the groups with MMT grades 0and 1 for any joint motion. Significant differenceswere observed for many other combinations of MMT
grades, with the following exceptions: MMT 1/2 forknee flexion (women); and MMT 0/2 (men andwomen), 1/2 (men and women), and 3/4 (men) for
ankle dorsal flexion.
Discussion
Previous reports suggested that the intratester[1, 13, 14] and intertester [15] reliability of DMT
was relatively high. In agreement, we found strong
correlations between F1 and F2 in the present
study, with the exception of ankle dorsal flexion
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Sawada K et al.: MMT measurements in clinical practiceTable 1. Results of manual muscle test (MMT) and handheld dynametric muscle test.
Joint
Hip

MotionFlexionExtension

Abduction

Average Fmax (SD) / number
MMT012Men

0.0 (0.0)/ 32

0.0 (0.0)/ 20

32.7(29.3)/ 48

71.7 (24.5) 114.8 (46.0) 174.0 (53.7)
/ 58
/ 110
/79

Women

0.0 (0.0)/ 22

0.8 (6.5)/ 64

20.4 (25.3)/ 107

59.4 (29.5)/ 129

Men0.0 (0.0)/ 14

1.1 (7.5)/ 43

33.6 (33.4)/ 67

71.7 (31.3) 110.8 (35.1) 162.2 (40.3)
/ 51
/ 88
/84

Women

3.2(13.8)/ 19

0.0 (0.0)/ 57

22.6 (24.3)/ 99

58.2 (36.0) 100.1 (37.5) 136.6 (38.9)
/ 125
/ 199
/ 108

Men

0.0 (0.0)/ 18

54.8 (41.8)/ 100

94.2 (37.4) 120.4 (39.2) 169.2 (47.8)
/ 47
/ 76
/ 75

40.2 (32.8)/ 172

80.3 (34.8) 101.2 (39.0) 134.2 (44.1)
/ 126
/ 178
/ 88

Women

Knee Flexion

Men
Women

Extension

Men
Women

n.s.
n.s.
n.s.

n.s.
2.1 (11.8)
/ 33
n.s.
0.0 (0.0)
5.1(13.6)
/ 13
/ 38
n.s.
1.2 (5.5)/ 44

7.0(17.0) 13.0 (15.6)
/ 33
/ 45
n.s.
0.0 (0.0)
2.3 (5.3)
10.7 (11.4)
/ 37
/ 55
/ 69
n.s.
n.s.
0.0 (0.0)
0.0 (0.0)
12.2 (16.1)
/ 52
/ 27
/ 55
n.s.
0.0 (0.0)
0.0 (0.0)
11.4 (28.7)
/ 54
/ 42
/ 74
n.s.

33.0(64.9) 19.8(59.2) 26.3 (29.0)
/ 82
/ 21
/ 23
n.s.
n.s.
n.s.
29.3(49.2) 18.9(414) 31.1 (35.9)
Women/ 75
/ 34
/ 46
n.s.
n.s.
n.s.

Ankle Dorsal flexion Men

measurements.
The presence of significant differences in Fmax
values between the adjacent MMT grades from grade
1 to 5 for the hip and knee motions (except between
MMT 1 and 2 in knee flexion for men) indicated thatthe grading was generally acceptable. However, DMT
results >0 N were obtained in a few cases with MMT
grades 0 or 1, where no muscle output was expectedbased on the definitions. This could partially originate
from compensatory motion in other joints. In thisregard, determination of MMT as grades 0 and 1
requires careful examination for any of the hip andknee motions.
Jpn J Compr Rehabil Sci Vol 8, 2017345

96.7 (35.8) 138.2 (38.4)
/ 213
/75

47.3 (27.2)/ 44

92.7 (40.0) 138.7 (52.8)
/ 92
/ 74

34.7 (21.6)/ 115

74.4 (30.7)/ 196

98.2 (35.1)/ 83

41.1 (46.3) 114.4 (59.1) 225.6(118.2)
/ 27
/ 53
/ 119
31.4 (30.8)/ 76

90.2 (60.1) 156.4 (68.0)
/ 125
/ 184

70.5 (47.0) 101.6 (47.5) 157.0 (46.2)
/ 35
/57
/ 108
n.s.
66.1 (51.7)/ 78

92.9 (39.0) 131.8 (41.0)
/ 140
/ 209

There were many cases with markedly different F1and F2 for ankle dorsal flexion. Significant differencesin the corresponding Fmax values were present
between contiguous MMT grades in the 2-5 range.
However, the average Fmax values were >30 and >20
N, respectively, for the cases with MMT grades 0 and1, where 0 N muscle output was expected according tothe definition. Ankle dorsal flexion requires especiallycareful assessment.
Despite such problems, MMT measurements wereconsidered generally acceptable regardless of gender,
because significant differences in muscle strength
were observed for the majority of pairs of MMT

Sawada K et al.: MMT measurements in clinical practicegrades.
This study has some limitations. First, muscle
power in healthy individuals has been reported to beaffected by age, side (dominant or non-dominant),height and weight in addition to gender [6, 7]. Although
the age of the study subjects was substantiallyrestricted by the limited time period in which
poliomyelitis had occurred, the effects of the otherfactors may need to be considered in future studies.
Second, inter- and intratester reliability was not
examined in this study. The examiner’s strength
reportedly limits the detection of moderate quadriceps
weakness via manual resistance [16]. It might benecessary to investigate the relationship between
MMT grades and quantified muscle strength obtained
during DMT for each examiner. On the other hand,
given that a large number of physical therapists
participated in the present study, the results may beconsidered to correspond to an average clinicalsituation. Furthermore, it may be easier to assign
MMT grades for many other disorders where theapparently healthy side can be used as a control.
Conclusions
Routine clinical MMT measurements are generallyacceptable, at least when they are performed byphysical therapists with 5 or more years of clinicalexperience.
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Jpn J Compr Rehabil Sci Vol 8, 2017