Thoracolumbar range of motion in baseball pitchers and position players

Optimal baseball throwing mechanics require a significant contribution of thoracolumbar motion, particularly in the sagittal and transverse planes. This motion is key for proper transmission of forces from the lower to upper extremity, thereby minimizing a throwing athlete's risk of injury and maximizing athletic performance.

To define the active-assisted thoracolumbar ROM of both baseball pitchers and position players and to compare these motions both within and between groups.

Fifty-six asymptomatic, collegiate and minor league baseball pitchers and 42 position players volunteered to participate. Active-assisted thoracolumbar flexion, extension, and bilateral rotation ROM, were measured in a standing position, using two bubble inclinometers. Two-tailed t tests were used to determine differences in ROM between and within the pitchers and position players.

The pitchers had significantly more rotation to the non-throwing arm side as compared to the position players (p = .007, effect size = .61). The pitchers also had more rotation to the non-throwing arm side as compared to their throwing side (p = .006, effect size = .47). There were no other significant differences between the pitchers and the position players (p > .53). Furthermore, the position players did not have a side-to-side rotation difference (p = .99).

Pitchers have a greater amount of rotation ROM towards the non-throwing arm side as compared to position players. Pitchers also have a greater amount of rotation ROM to the non-throwing arm side as compared to their throwing side rotation. Because pitchers often present with posterior shoulder tightness and subsequent altered shoulder horizontal adduction and internal rotation ROM, the increase in non-throwing side rotation ROM may occur in response to these adaptations. More specifically, this increase in non-throwing side trunk rotation ROM may allow such athletes to bring the arm across the body during the follow-through phase of the throwing motion despite posterior shoulder tightness. However, future research is necessary to investigate this relationship. Based on these results, clinicians should consider these thoracolumbar ROM adaptations in the prevention, evaluation, and treatment of baseball players.

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