Isokinetic Testing of the Shoulder Abductors and Adductors: Windowed vs Nonwindowed Data Collection

Presented at the Sports Physical Therapy Section Team Concept Meeting, December 1991, New Orleans, LA The manner of acquiring strength-testing data may influence the results of an investigation. The purpose of this study was to determine if a significant difference exists between windowed and unwindowed data collection during isokinetic testing of the shoulder abductors/adductors. Fifty healthy professional baseball pitchers participated in this study. Testing was performed on a Biodex isokinetic dynamometer at 180 and 300 degrees /sec for both the throwing and nonthrowing shoulders. Testing procedures regarding testing protocol, repetitions, positioning, and stabilization followed established guidelines for each subject. Statistical analysis was performed using a paired t-test with a p < 0.01 level of significance. Statistically significant differences were demonstrated between windowed and unwindowed mean peak torque data for both shoulders at both test speeds. The results indicated an average nonthrowing arm difference of 20.2 ft/lbs at 180 degrees /sec and 51.7 ft/lbs at 300 degrees / sec for the abductors. In each instance, the unwindowed mean peak torque values were higher than the windowed values, and significant end range torque spikes were elicited during unwindowed data collection. The nonthrowing adductors exhibited an average of 39.3 and 48.3 ft/lb differences at 180 and 300 degrees /sec, respectively. The throwing shoulder demonstrated average abductor differences of 25.6 ft/lbs at 180 degrees /sec and 47.7 ft/lbs at 300 degrees /sec. The average throwing adductor difference was 24.4 ft/lbs and 54.6 ft/lbs, respectively, at both test speeds. This investigation offers clinical relevance for those using isokinetic testing of the shoulder abductors/adductors in demonstrating the significant differences between windowed and unwindowed data, identifying torque spike data misinterpretation, and describing a clinical means of controlling aberrant torque production during testing. J Orthop Sports Phys Ther 1992;15(2):107-112.