Comparison of the Kyphosis Angle, Position, Muscles Strength, and Range of Motion of Shoulders in Volleyball Players With and Without Shoulder Impingement Syndrome

This case-control study aimed at comparing the kyphosis angle, position of the shoulder, the strength of rotator cuff muscles, and the range of shoulder motions in volleyball players with and without impingement syndrome.

The participants were 22 male professional volleyball players with at least 5 years of training experience. Eleven volleyball players with impingement syndrome and eleven without impingement syndrome were selected from accessible gyms by simple non-probabilistic sampling. The research tools were a flexible ruler, a measuring tape, a goniometer, a pull-up bar, a dynamometer, and tests to measure the distance between spinal midline and the shoulder, kyphosis angle, flexibility, range of motion, and isometric strength of the shoulder girdle muscles in abduction, adduction, flexion, extension, horizontal adduction, and horizontal abduction. Data were analyzed using SPSS V. 19 software and the Shapiro-Wilk test and independent t-test.

There was a significant difference between the two groups in terms of kyphosis angle, the distance between spinal midline and the shoulder, range of motion of the glenohumeral joint in abduction, and isometric strength of the shoulder girdle muscles in abduction, flexion, and extension (P<0.01). However, no significant difference was observed between the two groups in terms of flexibility of the shoulder when lying on the abdomen with arms stretched out in front, endurance in the strength of the shoulder girdle muscles, and isometric strength of the shoulder girdle muscles in adduction, horizontal adduction, and horizontal abduction (P>0.01).

The results of this study showed that angle of kyphosis, scapula distance to spine, range of motion of the shoulder, factor profile of a range of motion, and isometric muscle strength of shoulder girdle altered in people with shoulder impingement syndrome, and dysfunctions in these factors may result in shoulder impingement syndrome and athlete performance inefficiency.