Biomechanical Strategies for Minimizing Force Plate Targeting Effects during Running: Efficacy of Masked Force Plate Integration with Augmented Visual Feedback

This study aimed to investigate the targeting effect on the gait induced by the visual presence of a force plate during running and to develop a step guidance strategy (SGS) to minimize this effect and improve data acquisition success. Thirty-two healthy male participants were tested under three conditions: when the force plate was masked (MASK), when it was masked with the SGS implemented, and when it was visible (UNMASK). Kinematic, kinetic, and surface electromyography (sEMG) data were collected. The success rates for data acquisition were 30% for the MASK, 65.75% for the UNMASK, and 84.21% for the SGS condition. The UNMASK condition resulted in increased stride time, decreased stance time, and a lower coefficient of variation (CV) for the heel-to-force-plate distance. This condition also showed temporal variations in joint angles, an increased CV of the ankle joint angle waveform, significant alterations in ground reaction forces (GRF)-including greater peak braking force and impulses-and increased activation of the Vastus Medialis. The findings conclude that the visual presence of a force plate induces a targeting effect that undermines result reliability, and the proposed SGS effectively reduces this effect while significantly improving the success rate of data acquisition.