Effect of exercise-induced fatigue on position sense of the knee

Fatiguing isokinetic quadriceps exercises and the effect on the ability of 12 human subjects to reproduce knee angles was examined. The experimental and control procedures consisted of two separate test sessions conducted in sitting. Positioning was measured with a potentiometer. Accuracy was estimated by calculating the mean absolute error (AE) between five criterion and reproduction angles and the average directional or constant error (CE). Results showed a significant increase in target overshooting between the initial and final CE measurements on Day Two (experimental session) and Day One (control session). In contrast the control group showed no alteration in intrasession CE test performance. It is concluded that exercise-induced contractile fatigue can introduce bias into the encoding of positional information in a healthy knee.