Fatigue of the shoulder rotator muscles may negatively affect joint position sense (JPS) and ultimately lead to injury.
Recovery of shoulder JPS after muscle fatigue.
A repeated-measures study.
Musculoskeletal research laboratory.
Thirteen subjects participated in joint position error tests and isokinetic concentric strength assessment in shoulder rotation, before and after rotator muscle fatigue.
Local muscle fatigue was induced using isokinetic concentric contractions of the shoulder rotator muscles.
Main Outcome Measurements:
Shoulder rotator strength and JPS error signals were measured before fatigue, immediately after fatigue, and every ten minutes thereafter for one hour.
Before shoulder rotation muscle fatigue, the accuracy of shoulder JPS was 2.79 ± 1.67 degrees. After muscle fatigue, the accuracy decreased to 6.39 ± 2.90 degrees. Shoulder JPS was influenced up to 40 minutes after muscle fatigue, but shoulder strength was only affected for 10 minutes after muscle fatigue.
Proprioceptive recovery was slower than strength following fatigue of the shoulder rotators.