Effects of atrioventricular asynchrony on platelet activation: implication of thromboembolism in paced patients

OBJECTIVE: Shoulder rotator muscle imbalances can contribute to subacromial impingement. The forces and movement patterns of wheelchair locomotion may contribute to these imbalances. This study attempted to determine whether National Wheelchair Basketball Association players of differing classifications had significant differences (p < or = .05) in concentric isokinetic peak shoulder rotator torque and torque ratios, and wheelchair locomotion dependence. DESIGN: Fifty-seven (class 1 = 12, class 2 = 24, class 3 = 21) of 117 total tournament participants (class 1 = 25, class 2 = 49, class 3 = 43) served as the convenience sample of volunteers for the survey portion, and 33 of these subjects (class 1 = 11, class 2 = 12, class 3 = 10) also entered the isokinetic portion of this study. SETTING: National wheelchair basketball tournament. RESULTS: Class 1 and 2 players had greater wheelchair dependence than class 3 players (p < or = .05). Peak torque or torque ratios generally did not differ among player classifications or with other populations. Class 1 players had weaker nondominant shoulder external rotator torque production at 60 degrees/sec (p < or = .03) compared with other classes and at 180 degrees/sec compared with class 3 players (p = .02), suggesting an inability to develop the "attenuation of dominance" noted among other groups. Diminished torque-producing capacity at 60 degrees/sec related to greater wheelchair dependence among class 1 players (p = .034). CONCLUSIONS: Class 1 players failed to demonstrate the acquired shoulder external rotator torque symmetry evident among class 2 and 3 players (with specific weakness of the nondominant shoulder external rotators). This torque symmetry difference was related to their greater dependence on wheelchair locomotion.