Torque production in human upper and lower limb muscles with voluntary and electrically stimulated contractions

Two studies are reported in which the elbow flexor and extensor muscle groups and the quadriceps femoris muscle group in fifteen normal female subjects were tested under voluntary and electrically stimulated conditions. The torque produced during a maximum voluntary contraction (MVC) at each of six pre-determined joint angles was compared to the torque produced in maximum tolerated contractions (MTC) by two types of electrical stimulation (conventional interferential and high voltage stimulation). Results indicated a significant difference (p < 0.01) between the mean torque values produced by the MVC at all angles tested compared to the MTC. At the most favourable angle for producing an MTC, a mean torque of between 45 and 55% of an MVC for the elbow flexor and extensor muscles, and 65 to 74% for the quadriceps femoris muscle may be expected from both the high voltage and interferential stimulators.