Abstract
Context: Upper limb activities require a repetitive movement of the shoulder external rotator and abductor muscles. The malfunction of the proximal part of the upper limb kinetic chain tends to change the mechanics of the distal part and increase the risk of injuries. Objectives: To compare the normalized eccentric peak torque (NEPT) of the shoulder external rotator and abductor muscles among healthy athletes and those with tennis elbow and golfer's elbow. Design: An experimental crosssectional study. Setting: Isokinetic laboratory, Faculty of Physical Therapy, Cairo University. Participants: A total of 30 male athletes participated voluntarily in this study. Intervention: Participants were distributed into 3 groups: healthy group, tennis elbow group, and golfer's elbow group. Main Outcome Measures: NEPT of shoulder abductors and external rotators. The Biodex Isokinetic Dynamometer was used to measure the variables of interest. Results: There was a significant increase in the NEPT of shoulder abductors and external rotators in healthy control group compared with both tennis elbow and golfer's elbow groups at an angular velocity of 60 degrees/s (P < .05). Moreover, there was a significant increase in the NEPT of shoulder external rotators and abductors at an angular velocity of 120 degrees/s in healthy control group compared with tennis elbow group and in golfer's elbow group compared with tennis elbow group (P< .05). Conclusion: Tennis elbow and golfer's elbow are associated with decreased NEPT of shoulder external rotators and abductors compared with those of healthy athletes. This tends to decrease the external stability of the shoulder joint and put high stress on the distal joints of the upper kinetic chain.