CHANGES IN GROUND REACTION FORCES DURING RUNNING ON DIFFERENT SURFACES

1446 Running is a popular sport with approximately 40 million participants in the U.S. alone. The objective of this study was to determine the changes in force, ground contact time, and impulse for running on different surfaces. The cushioning and frictional properties of surfaces are blamed for causing running injuries by increasing loads beyond the limits of the musculoskeletal system. Data collected at the athlete-shoe interface may provide information about the forces directly applied to the living tissue and changes in gait dictated by the running surface. Five healthy adult males ran on four different surfaces: asphalt, concrete, grass, and track. Each recruit wore identical running shoes. Data were collected at 250Hz using an insole pressure measurement system. Analyses of Variance were used to detect differences among the surfaces. Post-hoc analyses were performed with the Student-Newman Keuls procedure. Significant differences were detected for force, contact time, and impulse (p < 0.05) among the surfaces. The highest ground reaction force and shortest contact time occurred for the track. The longest contact time occurred on concrete along with one of the lowest reaction forces. The largest impulse was detected on concrete. Times and forces varied depending on the surface. Therefore, impulse (force*time) may be the critical variable when evaluating the interaction between athlete and running surface. TableTable