Heart rate variability-guided recovery strategies and their effects on performance and injury risk in elite youth football players

This randomized controlled study investigated the efficacy of heart rate variability (HRV)-guided recovery on physiological, physical, and injury outcomes in elite youth football players. Thirty male players (age: 17-19 y; height: 183 ± 4 cm; body mass: 75 ± 6 kg) from a National Division club were assigned to HRV-guided recovery (HRV-GR; n = 15) or traditional recovery (TR; n = 15) over an eight-week, thrice-weekly training program. HRV-GR adjustments were individualized based on daily LnRMSSD, while TR followed standardized recovery routines. Primary outcomes included autonomic function (LnRMSSD, HRR), metabolic recovery ([La]), neuromuscular performance (CMJ, SJ), aerobic capacity (Yo-Yo IR1), and repeated sprint ability (RSA). Session RPE and non-contact injuries were also monitored. HRV-GR produced significantly greater improvements than TR in LnRMSSD (+18%; d = 1.02), HRR (+15%; d = 0.88), and post-exercise [La] reduction (-22%; d = 0.95). Neuromuscular performance gains were also higher in HRV-GR (CMJ +12%, SJ +10%; d = 0.80-0.85), alongside superior Yo-Yo IR1 distance (+14%; d = 0.90) and RSA maintenance (fatigue index -11%; d = 0.78). Session RPE decreased in HRV-GR despite equal external loads (-9%; d = 0.70). Injury incidence was reduced (2 vs. 7 cases in TR). These results indicate that HRV-guided recovery enhances parasympathetic reactivation, metabolic clearance, and neuromuscular readiness, translating into superior high-intensity intermittent performance and lower injury risk. Individualized HRV monitoring offers a practical, evidence-based approach to optimize training adaptation and mitigate fatigue in youth football.