Upper Quadrant Field Tests and Isokinetic Upper Limb Strength in Overhead Athletes.

Abstract

Isokinetic testing is used to determine possible deficits in upper extremity strength in overhead athletes. Given that isokinetic testing is restricted to a laboratory setting, field tests, such as the Seated Medicine Ball Throw (SMBT) and Upper Quarter Y-Balance Test (YBT-UQ), were developed to assess upper body performance. The relationships between these field tests and isokinetic strength have not been examined. To investigate the relationship between isokinetic strength testing for shoulder external and internal rotation and elbow flexion and extension and SMBT distance and YBT-UQ performance in overhead athletes. Cross-sectional study. Institutional laboratory. A total of 29 healthy overhead athletes (14 men, 15 women; age = 21.6 ± 2.5 years, height = 177.7 ± 9.7 cm, mass = 70.3 ± 11.5 kg). A Biodex dynamometer was used to measure the isokinetic strength of the shoulder and elbow muscles. Upper extremity performance was assessed using the SMBT and YBT-UQ. We used Pearson correlation coefficients and coefficients of determination to analyze the relationship between SMBT and YBT-UQ performance and the isokinetic strength variables. We observed moderate to strong correlations between the SMBT and isokinetic shoulder and elbow strength (r range = 0.595-0.855) but no correlations between the YBT-UQ and isokinetic strength variables. The shared variance between these strength variables and the SMBT ranged from 35.4% to 64.5% for shoulder strength and 58.5% to 73.1% for elbow strength. These findings suggested that the SMBT is a reliable, low-cost, and easy- and quick-to-administer alternative to isokinetic testing for evaluating upper extremity strength in a clinical setting. Performance on the YBT-UQ did not seem to be related to upper limb strength and, therefore, cannot be used for this purpose. Using the YBT-UQ for other purposes may have value.