Contralateral Trunk Tilt in High School Baseball Pitchers: Comparison and Relationship with Trunk Rotational Mobility, Compensatory Lateral Flexion, and Performance.

The study is underpowered by the authors' own standard: 19 pitchers were analysed where their power calculation called for 42, so a real relationship could have been missed. Every participant came from a single high school team recruited by convenience, so the results may not hold for other pitchers. Trunk rotation was measured in static quadruped positions on land, not during the pitch itself, so it is unconfirmed that those positions reflect what the trunk does while throwing. Pitchers threw from flat ground rather than a mound, which the authors note can change trunk mechanics. Right- and left-handed pitchers were pooled, and the direction of rotation can change how trunk rotation couples with sideways bending. Tilt was measured from the trunk as a single line, so the separate contributions of the thoracic spine, lumbar spine and pelvis could not be told apart. Measurements were taken at one point in time, so nothing here shows that one factor causes another. This group was mostly mobile, with only two of 19 pitchers below 50° of elbow-to-knee rotation, so a link between restricted mobility and excessive tilt may simply not have been testable here.

The authors report no conflicts of interest. No funding source is reported in the article text.

Do not read the lack of a relationship as proof that trunk rotation and the extra sideways lean are unrelated to how far a pitcher leans during throwing. The authors call their own study critically underpowered: 19 pitchers against the 42 their power calculation required, so a real relationship could have been missed and their non-significant findings do not rule one out.