Reducing the peak tibial acceleration of running by music-based biofeedback: A quasi-randomized controlled trial

Background: Running retraining with the use of biofeedback on an impact measure has been executed or evaluated in the biomechanics laboratory. Here, the execution and evaluation of feedback-driven retraining are taken out of the laboratory. Purpose: To determine whether biofeedback can reduce the peak tibial acceleration with or without affecting the running cadence in a 3-week retraining protocol. Study Design: Quasi-randomized controlled trial. Methods: Twenty runners with high peak tibial acceleration were allocated to either the retraining (n = 10, 32.1 +/- 7.8 years, 10.9 +/- 2.8 g) or control (n = 10, 39.1 +/- 10.4 years, 13.0 +/- 3.9 g) groups. They performed six running sessions in an athletic training environment. A body-worn system collected axial tibial acceleration and provided real-time feedback. The retraining group received music-based biofeedback in a faded feedback scheme. Pink noise was superimposed on tempo-synchronized music when the peak tibial acceleration was >= 70% of the runner's baseline. The control group received tempo-synchronized music, which acted as a placebo for blinding purposes. Speed feedback was provided to obtain a stable running speed of similar to 2.9 m center dot s(-1). Peak tibial acceleration and running cadence were evaluated. Results: A significant group-by-feedback interaction effect was detected for peak tibial acceleration. The experimental group had a decrease in peak tibial acceleration by 25.5% (mean: 10.9 +/- 2.8 g versus 8.1 +/- 3.9 g, p = 0.008, d = 1.08, mean difference = 2.77 [0.94, 4.61]) without changing the running cadence. The control group had no statistically significant change in peak tibial acceleration nor in running cadence. Conclusion: The retraining protocol was effective at reducing the peak tibial acceleration in high-impact runners by reacting to music-based biofeedback that was provided in real time per wearable technology in a training environment. This reduction magnitude may have meaningful influences on injury risk.