A Kinematic Analysis Of The Foot & Ankle During Progressive Baseball Swings

Baseball is a popular sport with over 15 million participants of all ages in 2018. Return to sport (RTS) following injury relies on interval programs involving progression through different swing types and effort levels. Hitting RTS protocols have been drastically understudied. Investigation of lower extremity biomechanics during hitting RTS programs could inform potential modifications to RTS programs, possibly based on specific lower extremity injuries. PURPOSE: Characterize ankle kinematics during 5 swing types at 3 effort levels to identify modifications that should be made to the progression. METHODS: Healthy Division I collegiate baseball players (n = 16, age = 20.5 ± 1.3 years) underwent biomechanical assessment during an RTS progression with 5 swing types [wiffle bat dry swing (DSw), regulation bat dry swing (DSr), tee (Tee), soft toss (ST), and pitching machine (PM)] each performed at low (25-50%), medium (50-75%), and high (75-100%) effort. Data was recorded using a 20 camera Motion Capture System (200 Hz). Ankle kinematics were analyzed from elbow drop to change in bat direction. To ease comparison across swing types, ball contact was simulated (sBC) as the point when the bat is parallel to the front of home plate. Differences across swing types, efforts, and ankles were determined by one way ANOVA and Bonferroni post-hoc test for pairwise comparisons (∝ = 0.05). RESULTS: The lead foot had significantly higher maximum adduction, while the back foot had significantly higher maximum abduction for all combinations of swing type and effort (p < 0.05, Fig1). CONCLUSIONS: Present results provide valuable information for physicians and other providers regarding the extent of ankle ab/adduction achieved during various stages of an RTS progression. Such information should be used to determine when an athlete begins and or advances through an RTS program based upon injury laterality and additional constraints imposed by each individual’s injury and recovery process.Major League Baseball