Detailled Information

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

Guide to assess muscle strength

This study compares the responsiveness to change of muscle strength, endurance and functional testing following induction therapy for severe myositis flare using the MRC-5 scale.

Systematic review that aims to provide an historical overview, literature review, description, synthesis and critique of the reliability and validity of MMT in the evaluation of the musculoskeletal and nervous systems.

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 MRC muscle scale grades muscle power on a scale of 0 to 5 in relation to the maximum expected for that muscle. 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 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. This scale has been expanded to a 10‐point scale in which the ability to resist against varying degrees of pressure in the antigravity position or the ability to move through varying ranges of motion in the gravity‐eliminated position earns either a plus (+) or minus (−) in association with a particular grade. 

Scores for individual muscle groups range from 0 –5 on the MRC scale, which is an ordinal grading scale. The scores are summed for a total score or for subscores involving particular muscle groups (proximal, distal, axial scores).