[[alternative]]Investigation of Shoulder Strengtg and Range of Motion among High Shool Pitchers

[[abstract]]The purpose of this investigation was to measure shoulder strength and range of motion among high school pitchers. Comparisons were made between dominant and non-dominant sides. Seven healthy high school varsity baseball pitchers participated in the study. The purpose and the procedures of this study were explained to the subjects and an inform consent form was signed by every subjects. A Cybex-6000 isokinetic dynamometer was used to measure shoulder range of motion, peak torque for internal rotation and external rotation for both concentric and eccentric strength. Five testing speeds were used for the measurement of the peak torque (30°, 60°, 90°, 180°, 240°/sec). A functional strength ratio was then determined by using the peak torque of eccentric external rotation over concentric internal rotation in this study. Paired t-tests were used to compare the peak torque and range of motion between dominant and non-dominant side and between concentric and eccentric peak torque at the same isokinetic testing speed. The relationship between contraction speed and peak torque was calculated by linear regression. The results of this investigation showed that the range of motion measurements were not significantly different (p>.05) between dominant and non-dominant sides. At the speed of 60°/sec test, the peak torque of concentric external rotation in the dominant was significantly (p<.05) larger than the peak torque in the non-dominant side, but the rest of the data did not show statistical significant differences between both sides. In the eccentric peak torque strength tests, the mean internal rotation peak torque of the dominant side was larger than the mean strength of the non-dominant side, but the mean external rotational peak torque of the non-dominant side was larger than the mean strength of the dominant side; however, the differences did not reach statistical significant level. The out put of the eccentric contraction strength was always larger than the concentric contraction strength at all testing speeds (p<.05). In the comparison of strength ratio (external rotation strength/internal rotation strength), non-dominant side was found significantly larger than the dominant side at the speed of 60° and 180°/sec concentric strength ratio. In the measurement of functional ratio, non-dominant side was 20% more than the dominant side. The data also showed that there was a negative linear relationship (Linear regression) between concentric peak torque strength and isokinetic contraction speeds. However, a linear relationship between the eccentric peak torque strength and isokinetic contraction speeds could not be found.