Effects of different warm-up periods on knee proprioception and balance in healthy young individuals.

CONTEXT There is limited information on the effects of different warm-up periods on proprioception and balance in the context of injury prevention. OBJECTIVE To determine the effects of warm-up exercises on knee proprioception and balance and to compare the effectiveness of warming up periods. DESIGN Pretest/posttest. SETTING Research laboratory. PARTICIPANTS 30 healthy subjects (19 women, 11 men; mean age 20.70 +/- 0.99 years). INTERVENTIONS Exercise groups performed warm-up exercises (group 1, 5 minutes; group 2, 10 minutes). Joint Position Sense (JPS) was tested at 15 degrees , 30 degrees , and 60 degrees knee flexion (KF) on a JPS device. Balance was measured using the Neurocom Balance Master System. MAIN OUTCOME MEASURES JPS absolute error (AE) was measured at 15 degrees , 30 degrees , and 60 degrees KF and postural control was measured. RESULTS After exercise, we found significant improvements for AE of JPSs of 30 degrees right (R) KF, 15 degrees left (L) KF, and 60 degrees L KF in group 1. In group 2, AE of JPS values increased for all angles of both knees except 60 degrees R KF. AE of JPS values of 15 degrees R KF, 30 degrees R KF, 15 degrees L KF, 60 degrees L KF were significantly different in group 2 compared with group 1. In balance measurements, there were significant improvements for standing on foam with eyes closed (EC) position, velocity and R-L unilateral stance EC in group 1. There were significant improvements for velocity, end point, maximum excursion, and L unilateral stance EC in group 2. CONCLUSIONS Both warm-up periods have positive effects on knee proprioception and balance. The 10-minute warm-up exercise improved proprioception by a greater amount than the 5 minutes warm-up exercise.