Abstract

The purposes of this study were to evaluate the Kinestim electrical stimulators ability to induce an isometric contraction torque of the quadriceps and to evaluate differences in torque production during maximal volitional contraction (MVC) and electrical stimulation superimposed on an MVC during isometric and isokinetic knee extension. Twenty women and 10 men with an age range of 21 to 33 years (mean age = 24.5 years) were tested. The Kinestim electrical stimulator delivered a 2,500 Hz, sinusoidal wave-form current modulated to 50 burst/second to the quadriceps femoris musculature. The intensity was adjusted to each subjects maximal tolerance. During the superimposed contraction (SC) conditions, torque output ranged from 93 to 104 percent MVC. There were no differences in torque production between the SC and MVC treatment conditions at 0 degrees/sec and 240 degrees/sec, but torque production at 60 degrees/sec was significantly less for SC than MVC. This study indicates that isometric and isokinetic SCs are not able to produce torque greater than a volitional contraction but they can produce a high percentage of a subjects MVC torque. Verf.-Referat