This study will be a prospective, repeated-measure, randomized clinical trial comparing shoulder outcome measures in adults with SAIS following eccentric or concentric progressive resistance exercise intervention programs. Subjects: 36 persons with SAIS, aged 18 and older, will be recruited from the Texas Health Resources Dallas outpatient rehabilitation department and referring physicians. Procedures: Participants will be randomly assigned to either a concentric or eccentric intervention group. Participants will complete outcome measures for pain intensity, shoulder function, shoulder pain-free active range of motion (AROM) of flexion and scapular plane elevation, and shoulder pain-free strength of external rotation and abduction. Outcomes will be assessed by an investigator blinded to group assignment at baseline and after three and six weeks of intervention. Interventions will consist of supervised exercise sessions three times a week. Exercise progression will follow a standardized and systematic approach. The reliability of the AROM and strength outcome measures will be assessed concurrently using a random subset of six participants from each group.
