The effect of scapular-retractor fatigue on external and internal rotation in patients with internal impingement.

CONTEXT: Scapular strengthening is thought to be an important component of the rehabilitation of patients with internal impingement.

OBJECTIVE

To determine the effect of scapular-retractor-muscle fatigue on internal- and external-rotation-torque production in patients with internal impingement.

DESIGN

Case control study.

SETTING

Outpatient clinic.

PARTICIPANTS

15 patients and 18 healthy subjects.

INTERVENTION: A scapular-retractor-fatigue protocol.

MAIN OUTCOME MEASURE: Shoulder-rotation-torque production.

RESULTS

After the scapular-retractor-fatigue protocol external-rotation strength was reduced in patients (involved 25%, noninvolved 19%; P < .001).

CONCLUSION

Fatigue in the scapular retractors resulted in lower shoulder-rotation-torque production. These findings emphasize the importance of the scapular retractors for proper function of the shoulder rotators with the arm in an abducted position in patients with internal impingement.