Effects of 6-week sling-based training of the external-rotator muscles on the shoulder profile in elite female high school handball players.

CONTEXT: In women's handball, the large numbers of throws and passes make the shoulder region vulnerable to overuse injuries. Repetitive throwing motions generate imbalance between shoulder internal- and external-rotator muscles. It has not yet been established whether sling-based training can improve shoulder external-rotator muscle strength.

OBJECTIVE

This study investigated the effectiveness of a 6-wk strengthening program in improving shoulder functional profile in elite female high school handball players.

DESIGN

Crossover study.

SETTING

National elite handball training center.

PARTICIPANTS

25 elite female high school handball players.

INTERVENTIONS: The program, completed twice per week for 6 wk, included sling-based strengthening exercises using a suspension trainer for external rotation with scapular retraction and scapular retraction alone.

MAIN OUTCOMES: Maximal shoulder external- and internal-rotation strength, shoulder external- and internal-rotation range of motion (ROM), and maximal throwing velocity were assessed preintervention and postintervention for dominant and nondominant sides.

RESULTS

After sling training, external- and internal-rotation strength increased significantly for both sides (P ≤ .001, and P = .004, respectively), with the result that there was no significant change in external- and internal-rotation strength ratios for either the dominant or the nondominant shoulder. No significant differences were observed for external-rotation ROM, while internal-rotation ROM decreased moderately, in particular in the dominant shoulder (P = .005). Maximal throwing velocity remained constant for the dominant arm, whereas a significant increase was found for the nondominant arm (P = .017).

CONCLUSIONS

This 6-wk strengthening program was effective in improving shoulder external-rotator muscle strength but resulted in a decrease in the ROM in shoulder internal rotation, while throwing velocity remained stable. Adding a stretching program to this type of sling-based training program might help avoid potential detrimental effects on shoulder ROM.