Changes in sitting posture affect shoulder range of motion

Abstract

To assess the effect of slouched sitting on shoulder range of motion (ROM). 30 asymptomatic males aged between 18 and 35 years with no history of shoulder problems within the last 6 months. Shoulder ROMs in flexion and abduction as well as external rotation and internal rotation in 90° of shoulder abduction were measured while the subjects sat in 3 different sitting postures. There were statistically significant mean differences among the 3 sitting postures regarding thoracic kyphosis and shoulder ROMs (p<0.001). Post hoc analyzes demonstrated significant differences in all comparisons (p<0.001). Changes in sitting posture affect shoulder ROMs in all directions tested. Greater changes in shoulder ROMs were associated with greater increase in thoracic kyphosis. These findings suggest that even subtle changes in thoracic kyphosis need to be considered during shoulder evaluation.