The effect of neurofeedback and EMG biofeedback on gastrocnemius, tibialis anterior, and peroneus longus time to peak EMG in elite athletes with chronic ankle instability: a randomized controlled trial

Ankle sprains are among the most common sports injuries and frequently progress to chronic ankle instability (CAI). Individuals with CAI often exhibit delayed reaction times in the peroneus longus and tibialis anterior muscles during mechanisms resembling ankle sprains. Neurofeedback and EMG biofeedback (myofeedback) have been reported to improve reaction time in some contexts. Given this background, we investigated whether a four-week neurofeedback or myofeedback program could improve calf-muscle activation timing in athletes with CAI. In this single-blinded, three-arm randomized controlled trial with a pretest-posttest and parallel group design, forty-five athletes with CAI (age 15–51 years) were recruited via convenience sampling and randomly allocated to control, Surface electromyography (EMG) biofeedback (myofeedback), or neurofeedback groups using a block randomization method. Training groups completed 12 sessions over four weeks (three sessions/week). During training, electrodes were applied and participants performed isolated ankle movements while receiving online feedback; the control group received no feedback training. Surface EMG recorded activity from the gastrocnemius, tibialis anterior, and peroneus longus during jump-landing and lateral-hopping tasks. A foot-switch provided the temporal reference. Outcomes were time to peak EMG (ms; time from foot-switch trigger to muscle activation) and EMG amplitude. Within-group pre–post changes were assessed with paired t-tests; between-group differences were examined with ANCOVA (baseline as covariate). Analyses were conducted in SPSS v23 with α=0.05. Six participants were lost to follow-up, resulting in a final per-protocol sample of 39. Neither the neurofeedback nor the myofeedback interventions produced significant within group changes in time to peak EMG or EMG amplitude for the gastrocnemius, tibialis anterior, or peroneuslongus during jump landing or lateral hopping; the control group also showed no significant pre–post changes (all p > 0.05). Consistent with these findings, between group comparisons of the change scores were non significant for all muscles and tasks (ANCOVA F (2, 35) ranged over = 0.492. to 2.037; all p > 0.05, η² ranged over = 0.028 to 0.107). In athletes with CAI, four weeks of EEG neurofeedback or EMG biofeedback did not reduce peri-ankle muscle time to peak EMG during jump-landing or lateral-hopping. These null findings highlight the challenge of applying laboratory feedback to sport-specific neuromuscular control. Future protocols should increase training dose, enhance task specificity, individualize targets, and integrate feedback with dynamic, closed-chain practice to improve transfer. https:// www.irct.ir (No. IRCT20190426043377N1); Registration date: 15-09-2019 (retrospectively registered).