Energy Flow Through the Arm Differs With Stride Length in College Pitchers

A study of twenty college baseball pitchers reports that the mechanical energy carried by the arm changes systematically with stride length, and that these changes track differences in ball speed. Mechanical energy in the proximal segments of the upper extremity at stride foot contact increased as the stride length extended, while mechanical energy in the distal segments at maximum external rotation of the shoulder was greater in the normal-stride condition than in either a shortened or a lengthened stride, a pattern consistent with the observed differences in ball speed.

Generating high ball speed is crucial for competitive pitching performance, and lower extremity mechanics play a key role in achieving it. Yet some previous studies have reported no significant difference in ball speeds despite differences in lower extremity mechanics, highlighting the need to examine how energy is transferred through the upper extremity to the ball under these conditions. To address this, Ryota Matsuda, Yuichi Hirano, Jun Umakoshi and Arata Kimura had twenty college baseball pitchers throw with an under-stride length and an over-stride length in addition to their normal-stride length, and analyzed the mechanical energy of the upper extremity segments at key events during pitching, together with the energy flow through each joint between those events.

The energy flow results followed the same proximal-to-distal pattern seen in the segment energy measurements. During the phase from stride foot contact to maximum external rotation, the energy flow to the upper arm through the shoulder joint was greater in the normal-stride condition than in the under-stride and over-stride conditions. The same condition pattern was observed for energy transfer through the elbow and wrist joints, and for ball speed itself, indicating that the normal stride supported greater energy delivery along the entire chain from shoulder to hand in this phase.

The most revealing result emerged where ball speed did not differ. Although no statistically significant difference in ball speed was observed between the under-stride and over-stride conditions, the JFP and STP components of shoulder energy flow showed different condition patterns between them. This suggests that the composition of shoulder energy flow may differ even when no statistically significant difference is observed in total energy flow into the upper arm, meaning that comparable ball speeds can be associated with distinct energy-transfer strategies at the shoulder. The authors note that this composition-level analysis is needed when evaluating how lower extremity mechanics relate to pitching performance, rather than relying on total energy flow values alone.

Subject of Research: The composition of energy flow in the upper extremity under different lower extremity mechanics in baseball pitching

Article Title: The composition of energy flow in the upper extremity under different lower extremity mechanics in baseball pitching

Article References: Matsuda, R., Hirano, Y., Umakoshi, J., & Kimura, A. (2026). The composition of energy flow in the upper extremity under different lower extremity mechanics in baseball pitching. PLOS One, 21(10), e0361030. https://doi.org/10.1371/journal.pone.0361030

Image Credits: AI Generated

DOI: 10.1371/journal.pone.0361030

Keywords: composition, energy, flow, upper, extremity, under, different, lower, mechanics, baseball, pitching, scientific research