Variables that Affect Pitch Velocity
Separation of hips and shoulders (1).
Baseball pitchers are constantly looking for adjustments in their delivery to increase their pitch velocity. However, an increase in the forces generated in throwing can lead to arm injury. The focus of the article reviewed was to see what factors can predict throwing velocity (1).
The article looked at 420 throwers with an average age of 14.7 (1). Using kinematic evaluation software from Dartfish Inc., the investigators measured different variables including having closed shoulders at hand-set position and if the pitcher had separation of rotation in the hips and shoulders (1).
They found four variables that correlated with pitch velocity. These included the age, height, hip and shoulder separation, and stride length (1). Separation of rotation within the hips and shoulders occurs when the pelvis has already rotated to face home plate and the shoulders in a right-handed pitcher face third base (1).
They found that a pitcher who was able to increase their stride length and add hip and shoulder separation could add 4.3% to their velocity (1). The separation of hip and shoulder can be explained using the summation of speed principle (1). This means that proximal trunk rotation will begin at the maximum angular velocity of the pelvis (1). The translation of motion can be aided by a strong core (1).
Overall, this study highlights the importance of hip and shoulder separation and the importance of a strong core.
References
Sgroi, Terrance, et al. “Predictors of Throwing Velocity in Youth and Adolescent Pitchers.” Journal of Shoulder and Elbow Surgery, vol. 24, no. 9, Sept. 2015, pp. 1339–45. PubMed, https://doi.org/10.1016/j.jse.2015.02.015.