Influence of Musculoskeletal Factors on the Biomechanics of Running

Abstract

The trunk, composed of thoracic and lumbar spine and surrounding muscles act as a key stabilizer and link between upper and lower body movement during running. Efficient trunk movement minimizes excessive rotation and lateral flexion is associated with improved running economy and reduced injury risk. This study serves the purpose of assessing the relationship between lateral trunk musculature endurance and trunk kinematics during running utilizing the side bridge hold time as a measure of core endurance and marker less capture to evaluate trunk kinematics. Nineteen Division 1 track athletes (ages 18-23) completed a side plank test and ran at three progressively faster speeds on an instrumented treadmill. Bilateral trunk rotation (BTR) and lateral flexion (LF) at foot contact were the kinematics selected for this study and were analyzed using three-dimensional markerless motion capture (Theia 3D; Visual 3D software). Kinovea video analysis software was used to quantify trunk instability during the side plank, using pixel-based displacement tracking from a marker placed on the anterior superior illiac spine. Using this information the average pixel displacement per second was determined, which was used to assess the athlete’s ability to stabilize during the side bridge. Normative data was generated by calculating percentile rankings for side plank hold times and corresponding average displacement, providing a benchmark for future comparisons in Division 1 running populations. Correlational analysis revealed a moderate positive relationship between side bridge hold times and left lateral flexion (r= 0.401), while other kinematic measures showed a weak or negligible correlation. These results suggest that static core endurance may not have a major influence over BTR and LF at foot contact during running, rather dynamic core endurance may possess a better correlation with these previously assessed kinematics