A Comparison of Torque Generated by Knee Extension With a Maximal Voluntary Muscle Contraction vis-a-vis Electrical Stimulation

In view of the Russian's claim that electrical stimulation can be used to increase muscle tension above the values generated by a maximum voluntary muscle isometric contraction, two experiments were conducted. Both compared torque values generated around the knee by a maximal voluntary isometric contraction first, to stimulation on its own and second, stimulation in conjunction with voluntary effort. Both experiments contrasted low and medium frequency currents. The first experiment used machines commonly available in therapy departments (N = 12). The second experiment used machines which approximate the Soviets' apparatus (N = 14). Comparisons which were made include: 1) Maximum voluntary contraction. 2) Low frequency current stimulation. 3) Medium frequency current stimulation. 4) “1” plus “2”. 5) “1” plus “3”. Results showed that no method was superior to maximal voluntary contraction. In each instance, the torque generated solely by any of the electrical devices was significantly inferior to voluntary effort. Voluntary effort in conjunction with stimulation was shown not to be significantly different from a voluntary maximal effort. The present studies did not substantiate the Soviet claim.