The purpose of present study was to compare the activated volume within quadriceps between treatments applied subjects with anterior cruciate ligament (ACL) reconstruction. Previously, we hypothesized that hindrance of afferent feedback from ACL could reduce the recruitment of motor units via attenuation of Ia afferents due to deactivation of gamma motor neuron. Based on the hypothesis, methods that activate gamma motor neuron and those that increase the recruitment of high-threshold motor units in the Quadriceps Femoris muscle could be effective rehabilitation methods. Four patients (4 males) with ACL reconstruction were enrolled in the present study. Three kinds of exercise-task (1. knee extension exercise, 2. knee extension with Neuromuscular Electrical Stimulation, 3. knee extension with sensory stimulation) were imposed to all subjects. The order of these tasks performed was randomly assigned. They performed four sets of 15 repetitions of a knee extension exercise. The % -activated volume were compared among exercise-tasks. We assume that each exercise-task would induce different response on the % -activated volume of each experimental group. However, the result of present study indicated that there was no significant difference among the groups.

DESCENTE SPORTS SCIENCE Vol.34/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE