Detailled Information

Medical Research Council. Aids to the investigation of the peripheral nervous system. London: Her Majesty’s Stationary Office; 1943 

This study documents the intrarater reliability of manual muscle test (MMT) grades in assessing muscle strength in patients with Duchenne's muscular dystrophy (DMD).

This study aims to validate manual muscle testing (MMT) for strength assessment in juvenile and adult dermatomyositis (DM) and polymyositis (PM).

This study summarizes the main outcome measures in adult and juvenile dermatomyositis, polymyositis, and inclusion body myositis.

MMT is a measure of muscle strength as part of the physical examination. No additional equipment is needed. MMT has been widely used in myositis therapeutic trials and clinical studies. It has been reported most often as a summary score of a total number of proximal, distal, and axial muscle groups tested bilaterally or as a proximal score that sums a number of proximal muscle groups from the upper and lower extremities.

Both the modified Medical Research Council (MRC) muscle strength scale and the Kendall grading scale are used.

More recently, MMT has been modified to a shorter version called MMT8, in which 8 proximal, distal, and axial muscle groups tested unilaterally closely approximate a total MMT score of 26 muscle groups tested bilaterally

The MRC scale for muscle power was first published in 1943; later on, in the 1970s the document was republished with the title "Aids to the Examination of the Peripheral Nervous System". The most commonly tested muscles include the shoulder abductors, elbow flexors, elbow extensors, wrist extensors, finger flexors, hand intrinsics, hip flexors, knee extensors, dorsiflexors, great toe extensor, and plantar flexors. 

The modified 0–10‐point Kendall grading scale provides firm definitions, along with plus (+) and minus (−) grades that provide an expanded scale.

The MRC grades were as follows: 0 = no contraction, 1 = flicker or trace of contraction, 2 = active movement with gravity eliminated, 3 = active movement against gravity, 4 = active movement against gravity and resistance, and 5 = normal power. Scores for individual muscle groups range from 0 –5 on the MRC scale, which is an ordinal grading scales. The scores are summed for a total score or for subscores involving particular muscle groups (proximal, distal, axial scores).

Using the Kendall 0–10 scale, the total MMT score ranges from 0–260 when 12 muscle groups are tested bilaterally along with 2 axial muscle groups. A proximal score of 0–160 represents 8 muscle groups tested bilaterally, a distal score of 0–80 includes 4 muscle groups tested bilaterally on the Kendall scale, and an axial score of 0–20 tests neck flexors and extensors. Normal strength is represented by a higher score at or near the top of the scale. The following interpretations of the scores of individual muscle groups have been used by researchers using MMT to study myositis: a muscle group graded from 0–3 on the Kendall scale indicates severe weakness, grade 4–6 indicates moderate weakness, grade 7–9 indicates mild weakness, and grade 10 indicates no detectable weakness