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

Background: 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.

Research question: What is the effect of sand training on running mechanics in individuals with anterior cruciate ligament reconstruction and pronated feet?

Methods: 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.

Results: 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).

Significance: 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.