Analysis of the Global Structure in Pitching Motion Connecting Preparatory Kinematics to Resulting Ball Velocity

In many athletic movements, motion in one phase influences motion in subsequent phases, creating a whole-body kinetic chain from the initiation of preparatory movements to the completion of the primary movement.Understanding how movement components within each phase are related to each other and how these relationships collectively form an overall structure of the target movement can facilitate the motor learning process.However, conventional methods have difficulty analyzing such an overall structure involving dependencies among many movement components.To address this limitation, this study proposes a novel analytical framework to elucidate the structural relationships among preparatory movements, subsequent primary movements, and final performance outcomes.The method employs graphical lasso, a machine learning technique that estimates conditional dependencies and infers a sparse graph structure.Analysis of 50 baseball pitchers demonstrated that preparatory movements were not directly associated with achieved ball velocity but were indirectly connected through primary movements following stride-foot contact.Specifically, a "hip-first" posture, in which the trunk leads the upper and lower limbs at the onset of weight transfer, was associated with increased ball velocity.These findings underscore the utility of the proposed framework for enhancing our understanding of the overall structure of complex athletic movements.