EFFECTS OF PROPHYLACTIC KNEE BRACING ON LOWER-EXTREMITY JOINT POSITION AND MUSCLE ACTIVATION DURING RUNNING

The primary purpose of a prophylactic knee brace is to decrease injury potential without compromising joint function; however, the extent th at these devices can alter knee muscle function is not clear. This stu dy investigated effects of nonprescription prophylactic knee bracing o n lower extremity joint position and muscle activation during running. Six healthy male college-aged recreational runners used a motor-drive n treadmill under 6 conditions: fast or slow speeds, with and without wearing a prophylactic knee brace, and with and without wearing a weig hted vest. Changes in hip, knee, and ankle joint position and electrom yographic activity from 9 lower extremity muscles were monitored durin g the running cycle weightbearing phase. Results revealed significant changes (P < 0.05) in joint position and electromyographic activity fo r comparisons of slow versus fast, braced versus nonbraced, and weight ed versus nonweighted conditions. From 83% to 89% of the braced and no nbraced comparisons generated significant differences in knee joint po sition while significant hip and ankle joint position changes occurred in 50% to 58% of comparisons. From 67% to 83% of braced and nonbraced comparisons for the 9 muscles produced significant differences in ele ctromyographic activity. Findings suggest that neuromuscular control i s altered when external prophylactic devices are applied.