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

POSTPRINT.

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 accel-eration 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 accelera-tion 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 ~2.9 m·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 accelera-tion 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 ac-celeration 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.