Investigating the effect of sand training on running mechanics in individuals with anterior cruciate ligament reconstruction and pronated feet

Running on sand could be a method for the rehabilitation of individuals with anterior cruciate ligament reconstruction and pronated feet. However, there is a lack of knowledge about the effects of running on sand on running biomechanics and muscle activities. What is the effect of sand training on running mechanics in individuals with anterior cruciate ligament reconstruction and pronated feet? Twenty-eight adult males with anterior cruciate ligament reconstruction and pronated feet were divided into two equal groups (intervention and active control groups). Participants were asked to run at a constant speed of ∼3.2 m/s over an 18 m runway, respectively. Ground reaction forces were recorded using a Bertec force plate. Muscle activities were recorded using a surface bipolar electromyography system. In intervention group but not control group, post-hoc analysis demonstrated significantly longer time-to-peak of impact vertical ground reaction force at post-test than that pre-test (p = 0.047). In intervention group but not control group, post-hoc analysis demonstrated significant decreases of semitendinosus activities during push-off at post-test compared with the pre-test (p = 0.005). Sand training improved time-to-peak of ground reaction forces (e.g., time-to-peak of peak of impact vertical ground reaction force) and muscle activities (e.g., semitendinosus activities) in adult males with anterior cruciate ligament reconstruction and pronated feet. •Longer time-to-peak of impact reaction force was observed after sand training.•Lower semitendinosus activities during push-off was observed after sand training.•Greater tibialis anterior activity was observed at intervention than controls.