Rw. Bohannon et D. Corrigan, A broad range of forces is encompassed by the maximum manual muscle test grade of five, PERC MOT SK, 90(3), 2000, pp. 747-750
This retrospective study summarizes the range of knee extension forces asso
ciated with the manual muscle lest grade of 5. The range of the forces (>56
0 Newtons) was large and encompassing of more than 86% of measurable forces
. These findings help to explain the insensitivity of manual muscle testing
and why it has such a profound ceiling effect.