Changes in Shoulder Kinematics Following an Isokinetic Fatigue Protocol in Tennis Players

We will use an isokinetic dynamometer to conduct the concentric isokinetic fatigue protocol. The start position is shoulder abduction 90°, elbow flexion 90°and range of motion is set from 0 ° (internal rotation) to 90 ° (external rotation) under 120°/s. To calculate maximum torque of shoulder external and internal rotation, the subject will perform maximum isokinetic test 5 times before fatigue. Fatigue protocol include 10 sets, and each set include 32 repetitions with 30 seconds of rest between sets. The fatigue protocol will be stopped under three conditions: 1. the torque decreases 50% of maximum torque three times in one set or 2.rating of perceived exertion (RPE) abrove 15 and players can not perform the fatigue protocol or 3. finish the whole test.