Data Analysis

Descriptive statistics were calculated for selected demographic variables. A paired, two-tailed t-test was used to calculate differences in shoulder and hip ROM and strength between preseason and postseason. Preseason to postseason changes were analyzed based on 127 individual player seasons where each athlete’s preseason data was matched to that same athlete’s postseason data. Paired, two-tailed t-test with equal variance was used to compare differences between dominant and non-dominant preseason shoulder and hip ROM and strength. Preseason averages for the pitcher group and player group were calculated using a weighted average method to account for certain athletes who completed more preseason measurements than others. For example, a weighted average value for an athlete participating for three seasons was calculated as follows:

Unpaired two-tailed t-test assuming unequal variance was used to compare preseason pitchers to position players shoulder and hip ROM and strength. Preseason averages for pitcher and position player groups were calculated using the same weighted average method as described previously. Given the multiple t-tests performed comparing side-to-side data and pitchers to position players, a Bonferroni correction was performed to adjust the α value and minimize the likelihood of Type I error.