Manual Muscle Test

Spinal Cord Injury:

(Herbison et al, 1996, n = 88, C4-C8 AIS A-D, 0-2 years post injury, measured C5 elbow flexor strength)

• Excellent interrater reliability (ICC = 0.94)

Convergent Validity

SCI:

(Schwartz et al, 1992, n = 122)

Correlation between MMT and Myometry: Time post SCI

Muscle

72 hours

1 week

1 month

3 months

6 months

12 months

L bicep

0.86**

n = 31

0.84**

n = 30

0.68**

n = 37

0.82**

n = 33

0.59*

n = 24

0.42*

n = 20

R bicep

0.80**

n = 29

0.83**

n = 29

0.79**

n = 26

0.68**

n = 34

0.59*

n = 23

0.18

n = 20

L ECR

0.92**

n = 15

0.86**

n = 22

0.81**

n = 30

0.84**

n = 21

0.84**

n = 16

0.77**

n = 18

R ECR

0.94**

n = 18

0.78**

n = 19

0.93**

n = 26

0.79**

n = 24

0.75**

n = 17

0.71**

n = 17

** = Excellent correlation > 0.6

* = Adequate correlation 0.31-0.59

SCI:

(Noreau, Vachon, 1998, n = 38 level of injury C5-L3, AIS A-D)

Spearman Correlation Coefficients between MMT and Myometry

Muscles

Paraplegia at Admit (n = 23)

Paraplegia at Discharge (n = 23)

Tetraplegia at Admit (n = 15)

Tetraplegia at Discharge (n = 15)

Elbow flexors

0.48*

0.26

0.58**

0.48*

Elbow extensors

0.46*

0.55*

0.95**

0.88**

Shoulder flexors

0.63**

0.60**

0.83**

0.50*

Shoulder extensors

0.44*

0.49*

0.67**

0.57*

Shoulder abductors

0.64**

0.57*

0.55*

0.59*

Shoulder adductors

0.67**

0.34*

0.84**

0.73**

** = Excellent correlation > 0.6

* = Adequate correlation 0.31-0.59

Osteoarthritis (OA):

(Youdas et al, 2010; n = 20 subjects with OA and 20 healthy subjects; mean age = 53.4(9.0) for subjects with OA and 50.4(7.2) for healthy subjects)

• SEM for right side MMT using handheld dynanometer (HHD) = 1%
• SEM for left side MMT using handheld dynanometer (HHD) = 2%

Osteoarthritis (OA):

(Youdas et al, 2010)

• MDC for right side MMT using handheld dynanometer (HHD) = 4%
• MDC for left side MMT using handheld dynanometer (HHD) = 4%

Osteoarthritis (OA):

(Youdas et al, 2010)

• Excellent test-retest reliability for right side (ICC = 0.98)
• Excellent test-retest reliability for left side (ICC = 0.97)

Osteoarthritis (OA):

(Youdas et al, 2010)

• Sensitivity = 0.35
• Specificity = 0.90
• Positive likelihood ratio = 3.5

Trapezius Muscle: (Cibulka et al., 2013; n = 11; mean age = 20-31 (23.8) years; mean height 173.9 cm, mean weight 76.2 kg, mean body mass index of 25.0 (SD = 2.2))

The mean and SD for normalized percentages of maximal voluntary isometric contraction (MVIC) for the new trapezius MMT.

Muscle

% Mean MVIC

SD

Upper trapezius

160.84

58.78

Middle trapezius

59.23

21.21

Lower trapezius

47.54

14.86

The mean and SD’s torque for upper, middle, lower, and new trapezius muscles. These were measured with a Microfet 2 Dynamometer in kilograms.

Muscle test

Mean Torque (kg)

SD

Upper trapezius

9.0

1.8

Middle trapezius

4.2

1.3

Lower trapezius

4.1

1.6

New trapezius

5.8

1.8

Trapezius Muscle: (Cibulka et al., 2013)

• Excellent test-retest reliability:
  • Upper trapezius testing: (ICC = 0.88 [95% CI: 0.62-0.97])
  • Middle trapezius testing: (ICC = 0.94 [95% CI: 0.78-0.98])
  • Lower trapezius testing: (ICC = 0.89 [95% CI: 0.560-0.97])
  • New trapezius testing: (ICC = 0.92 [95% CI: 0.70-0.98])

ICU survivors and simulated patients:

(Fan et al, 2010, n = 19, 26 muscle groups, 19 clinicians)

• Adequate to Excellent overall interrater reliability of Upper extremity muscles (ICC = 0.62-1.00)
• Adequate to Excellent overall interrater reliability of Lower Extremity muscles (ICC = 0.66-1.00)

Myositis (Pfister et al., 2018; n=46)

• SEM using intrarater reliability was 1.8% (2.5)
• SEM using interrater reliability was 2.2% (3.1)

Myositis (Pfister et al., 2018; n=46)

• MDC using intrarater reliability = 4.9% (6.9)
• MDC using interrater reliability = 6.2% (8.6)

Myositis (Pfister et al., 2018; n=46)

MMT8 total score mean (+/-SD)

• Measurement 1 = 70+/-8
• Measurement 2 = 71+/-7
• Measurement 3 = 72+/-7

Myositis (Pfister et al., 2018; n=46)

• Excellent Intrarater reliability ICC (95%CI) = 0.94 (0.90-0.97)
• Excellent Interrater reliability ICC (95%CI) = 0.91 (0.83-0.95)

Inflammatory Myopathies: (Rider, L.G. et al., 2010; n=73 children, 45 adults; mean age=10.2 (5.6), 42 (17.2) years; using Kendall’s 0-10 point scale)

• Excellent intrarater reliability for juvenile IIM: ICC range from 0.84-0.95
• Adequate interrater reliability for juvenile IIM: ICC range from 0.68-0.76

Idiopathic Inflammatory Myopathies (IIM): (Rider, L.G. et al., 2010; n=73 children, 45 adults; mean age=10.2 (5.6), 42 (17.2) years; using Kendall’s 0-10 point scale)

• Excellent internal consistency for total MMT for juvenile IIM (Cronbach’s alpha = 0.97) and adult IIM (Cronbach’s alpha = 0.93)
• Excellent internal consistency for proximal MMT for juvenile IIM (Cronbach’s alpha = 0.96) and adult IIM (Cronbach’s alpha = 0.93)
• Excellent internal consistency for MMT6 subset #118 for juvenile IIM (Cronbach’s alpha = 0.85)
• Adequate internal consistency for MMT6 subset #118 for adult IIM (Cronbach’s alpha = 0.78)
• Adequate to excellent internal consistency for MMT8 subsets (Cronbach’s alpha = 0.78-0.91)

Description of muscle groups and their percentage MMT score values in juvenile and adult patients with IIM*

MMT score

Muscle groups included in score

Juvenile IIM (n = 73)

Adult IIM (n = 45)

Total MMT†

Neck flexors, neck extensors, trapezius, deltoid, biceps, iliopsoas, gluteus maximus, gluteus medius, quadriceps, wrist flexors, wrist extensors, ankle dorsiflexors, ankle plantar flexor

88.3 (79.0, 94.1)

78.2 (73.1, 84.0)

Proximal MMT‡

Trapezius, deltoid, biceps, iliopsoas, gluteus maximus, gluteus medius, quadriceps

87.6 (78.7, 94.2)

72.4 (66.3, 81.2)

MMT6 subset #118§

Neck extensors, trapezius, gluteus maximus, iliopsoas, wrist extensors, ankle dorsiflexors

86.7 (78.0, 94.3)

80.0 (74.3, 85.9)

MMT8 subsets¶

 Subset #13

Neck flexors, trapezius, deltoid, gluteus maximus, iliopsoas, quadriceps, wrist flexors, ankle dorsiflexors

86.8 (77.1, 92.7)

78.5 (71.7, 81.6)

 Subset #55

Neck flexors, deltoid, biceps, gluteus maximus, gluteus medius, quadriceps, wrist flexors, ankle dorsiflexors

87.5 (76.6, 92.3)

76.8 (70.1, 81.3)

 Subset #58

Neck flexors, deltoid, biceps, gluteus maximus, gluteus medius, quadriceps, wrist extensors, ankle dorsiflexors

86.8 (76.4, 92.5)

76.5 (69.7, 80.9)

 Subset #88

Neck extensors, trapezius, deltoid, gluteus maximus, iliopsoas, quadriceps, wrist extensors, ankle dorsiflexors

87.5 (79.6, 94.4)

79.0 (72.8, 84.1)

 Subset #133

Neck extensors, deltoid, biceps, gluteus maximus, iliopsoas, quadriceps, wrist flexors, ankle dorsiflexors

87.3 (77.1, 94.8)

77.3 (71.1, 81.8)

 Subset #136

Neck extensors, deltoid, biceps, gluteus maximus, iliopsoas, quadriceps, wrist extensors, ankle dorsiflexors

87.3 (76.7, 94.4)

77.3 (70.1, 81.8)

 Subset #142

Neck extensors, deltoid, biceps, gluteus medius, iliopsoas, quadriceps, wrist extensors, ankle dorsiflexors

89.0 (78.4, 94.3)

78.5 (70.3, 83.4)

• * Values are the median (25th, 75th percentiles). Scores are expressed as a percentage of the maximum potential score. MMT = manual muscle testing score; IIM = idiopathic inflammatory myopathies; MMT6 = 6 muscle group MMT.
• † Proximal and distal muscle groups tested bilaterally; maximum potential score = 240.
• ‡ Muscle groups tested bilaterally; maximum potential score = 140.
• § Muscle groups tested unilaterally on the right side; maximum potential score = 60.
• ¶ Muscle groups tested unilaterally on the right side; maximum potential score = 80.

Myositis (Pfister et al., 2018; n=50; mean age=56 (14.0) years; time since diagnosis=36 (18) months)

• Excellent convergent validity between MMT with averaged force of hand-held dynameter of shoulder abduction (r = 0.85), neck flexion (r = 0.62), and hip abduction (r = 0.61)
• Adequate convergent validity between MMT with averaged force of hand-held dynameter of elbow flexion (r = 0.55)
• Poor convergent validity between MMT with averaged force of hand-held dynameter of wrist extension (r = .27), knee extension (r = 0.28), ankle extension (r = 0.24), and hip extension (r = 0.28)
• Excellent convergent validity between MMT with normalized force of hand-held dynameter of shoulder abduction (r = 0.75) and hip abduction (r = 0.65)
• Adequate convergent validity between MMT with normalized force of hand-held dynameter of elbow flexion (r = 0.54), neck flexion (r = 0.57), and hip extension (r = 0.38)
• Poor convergent validity between MMT with normalized force of hand-held dynameter of wrist extension (r = 0.19), knee extension (r = 0.27), and ankle extension (r = 0.09)

Idiopathic Inflammatory Myopathies (IIM): (Rider, L.G. et al., 2010; n=73 children, 45 adults; mean age=10.2 (5.6), 42 (17.2) years; using Kendall’s 0-10 point scale)

• Excellent correlation between Total and Proximal MMT scores in juvenile IIM with distal and axial MMT scores (rs =0.73–0.88, P < 0.000)
• Adequate to excellent correlation between Total and Proximal MMT scores in adult PM/DM with distal and axial MMT scores (rs= 0.40 – 0.74, P < 0.008).
• Adequate correlation Total and Proximal MMT scores in adult PM/DM correlated with lactate dehydrogenase (rs = -0.45 to -0.50, P = 0.007–0.016).
• Adequate correlation with creatine kinase (CK), aldolase, and aspartate aminotransferase (rs = -0.30 to -0.38, P = 0.012–0.055).
• Adequate correlation between Prednisone dose with Total, Proximal, and best MMT subset scores in juvenile IIM (rs = -0.33 to -0.39, P  ≥ 0.005)
• Poor correlation between Prednisone dose with Total, Proximal, and best MMT subset scores in adult PM/DM (rs = -0.11 to -0.22, P > 0.18)
• Adequate correlation between total MMT and Physician Global Activity for juvenile IIM (rs = -0.54) and adult IIM (rs = -0.33)
• Excellent correlation between total MMT with Childhood Health Assessment Questionnaire (rs = -0.62), Childhood Myositis Assessment Scale (rs = 0.70), and Convery activities of daily living (rs = 0.63)
• Adequate correlation between total MMT with MRI STIR + T1-weighted average for juvenile IIM (rs = -0.48) and adult IIM (rs = -0.43)
• Poor to adequate correlation between total MMT and creatine kinase in juvenile IIM (rs = -0.16) and in adult IIM (rs = -0.34)
•  

Convergent construct validity (rs) of MMT scores with measures of myositis activity and damage*

MMT score

Total MMT

Proximal MMT

Physician Global Activity

C‐HAQ

ADL

CMAS

MRI STIR + T1‐weighted average

Creatine kinase

Juvenile IIM (n = 73)

Adult IIM (n = 45)

Juvenile IIM (n = 73)

Adult IIM (n = 45)

Juvenile IIM (n = 73)

Adult IIM (n = 44)†

Juvenile IIM (n = 58)

Adult IIM (n = 45)

Juvenile IIM (n = 69)

Juvenile IIM (n = 31)†

Adult IIM (n = 45)†

Juvenile IIM (n = 73)‡

Adult IIM (n = 45)†

Total MMT

1.0

1.0

0.96

0.91

−0.54

−0.33

−0.62

0.63

0.70

−0.48

−0.43

−0.16

−0.34

Proximal MMT

0.96

0.91

1.00

1.00

−0.47

−0.34

−0.59

0.70

0.73

−0.48

−0.50

−0.12

−0.38

MMT6 subset #118

0.97

0.95

0.92

0.81

−0.54

−0.31

−0.68

0.61

0.71

−0.49

−0.43

−0.13

−0.36

MMT8 subsets

 Subset #13

0.98

0.96

0.96

0.87

−0.48

−0.39

−0.61

0.55§

0.71

−0.45

−0.45

−0.16

−0.43

 Subset #55

0.98

0.96

0.95

0.91

−0.48

−0.37

−0.62

0.57§

0.69

−0.45

−0.45

−0.13

−0.37

 Subset #58

0.98

0.96

0.95

0.91

−0.49

−0.37

−0.64

0.59

0.70

−0.45

−0.46

−0.13

−0.36

 Subset #88

0.98

0.97

0.95

0.89

−0.50

−0.34

−0.66

0.63

0.73

−0.47

−0.42

−0.12

−0.37

 Subset #133

0.99

0.98

0.95

0.90

−0.51

−0.34

−0.63

0.62

0.69

−0.47

−0.44

−0.14

−0.38

 Subset #136

0.98

0.97

0.94

0.90

−0.51

−0.34

−0.63

0.64

0.69

−0.48

−0.45

−0.15

−0.38

 Subset #142

0.98

0.96

0.94

0.91

−0.49

−0.33

−0.60

0.66

0.67

−0.45

−0.44

−0.15

−0.33

• * P < 0.0001 unless otherwise indicated. MMT = manual muscle testing; C‐HAQ = Childhood Health Assessment Questionnaire; ADL = Convery activities of daily living; CMAS = Childhood Myositis Assessment Scale; MRI = magnetic resonance imaging; IIM = idiopathic inflammatory myopathy; MMT6 = 6 muscle group MMT. See Table 2 for testing methodology.
• † P = 0.001–0.05.
• ‡ P > 0.05.

§ P = 0.0001–0.0009.

Idiopathic Inflammatory Myopathies (IIM): (Rider, L.G. et al., 2010; n=73 children, 45 adults; mean age=10.2 (5.6), 42 (17.2) years; using Kendall’s 0-10 point scale)

Content validity of the MMT was determined by a panel of expert pediatric and adult PTs, and Rheumatologists experienced in evaluating myositis. Each expert ranked items quantitatively and qualitatively and recorded whether a particular muscle group could not be tested accurately.  From the results of this panel, concluded that the instrument has strong content validity (Rider, L.G. et al., 2010).

Rider, L.G. (2010) states that, “The top-rated 8 muscle group subsets also had acceptable face validity, included frequently involved muscle groups, and were felt to be easier to test, even in patients with joint contractures or calcinosis. However, they require prospective validation, including in therapeutic trials, to further define their performance characteristics in other populations (p. 471).”

Myositis (Pfister et al., 2018; n=50; mean age=56 (14.0) years; time since diagnosis=36 (18) months)

• Adequate ceiling effects of <5% for total score
• Poor ceiling effects of 22-82% for various muscle groups

Idiopathic Inflammatory Myopathies (IIM): (Rider, L.G. et al., 2010; n=73 children, 45 adults; mean age=10.2 (5.6), 42 (17.2) years; using Kendall’s 0-10 point scale)

Standardized response means for Total MMT was 0.56 in juvenile IIM and 0.75 in patients with adult PM/DM. Using relative efficiencies, the Proximal MMT score was slightly less responsive relative to the Total MMT score in juvenile IIM, but slightly more responsive in adults with PM/DM (Rider, L.G. et al., 2010).

•  Relative efficiency of MMT subgroups were found (>0.90)

Children with Spina Bifida (Mahoney et al., 2009; n=20; mean age = 9 years and 10 months)

Muscle Group

SEM

Hip Flexors

0.4

Hip Abductors

0.5

Knee Extensors

0.5

Children with Spina Bifida (Mahoney et al., 2009; n=20; mean age = 9 years and 10 months)

The 90% confidence level was chosen. Therefore, the MDC represents the change needed to be 90% confident that actual change occurred.

Muscle Group

MDC 90%

Hip Flexors

0.85

Hip Abductors

1.27

Knee Extensors

1.13

Children with Spina Bifida (Mahoney et al., 2009)

• Excellent interrater reliability for hip abductors: ICC = 0.75
• Adequate interrater reliability for knee extensors: ICC = 0.40
• Poor interrater reliability for hip flexors: ICC = 0.37