Effects of non-invasive neuromodulation on sleep quality and recovery in elite female football players

articipants allocated to the intervention will receive non-invasive microcurrent neuromodulation using the NESA device system. Standardized surface electrodes are placed on both hands and both feet, plus one directing electrode that varies by phase (see below). Sessions are delivered four times per week, 60 minutes each, for 8 weeks (32 sessions total). Intensity: device “Low” setting (microcurrent; not perceptible to participants). Frequencies: within 1–15 Hz, delivered as bioelectric pulse trains (up to ~19,000 pulses/min); frequency may be fixed or variable within this range by program. Provider: Licensed physiotherapists trained in the clinical use of the NESA system and not involved in outcome assessment. Five progressive phases (program order and durations within each 60-min session): - Phase 1 (Week 1; acclimation; directing electrode at C6–C7): P1: 15 min. P2: 15 min. P7: 15 min. P8: 15 min. - Phase 2 (Week 2; circadian/sleep focus; directing electrode frontal midline): P2: 20 min. P4: 20 min. P5: 20 min. - Phase 3 (Weeks 3–4; autonomic regulation; directing electrode at C6–C7): P7: 40 min. P8: 20 min. - Phase 4 (Weeks 5–7; performance/recovery; directing electrode at C6–C7): P2: 15 min. P7: 30 min. P8: 15 min. - Phase 5 (Week 8; consolidation; directing electrode at C6–C7): P7: 45 min. P8: 15 min. Programs used and how they differ (as per protocol): - Program 1 (P1): Alternating stimulus times with frequencies ~3.85–7.69 Hz, sequential delivery across the 24 electrodes, multiple pauses, alternating polarity. - Program 2 (P2): Frequencies ~1.14–1.96 Hz with input pathways emphasising distal channels of upper/lower limbs; sequencing oriented ventrally. - Program 4 (P4): Preset pattern with lower-frequency ranges and sustained cycles to support sleep-related scheduling (used in circadian phase). - Program 5 (P5): Preset pattern with progressive sequencing/duty cycle adjustments (used in circadian phase). - Program 7 (P7): Alternating stimulus times with frequencies ~1.92–14.29 Hz, symmetric positive/negative pulses; multi-channel sequencing. - Program 8 (P8): Sequential stimuli with stable frequency ~7.69 Hz, symmetric polarity across channels. Adherence/fidelity monitoring: - Attendance logs for each session (start/stop times). - Electrode placement checklist (location, integrity, skin preparation). - Session record of program(s), order, and exact programmed durations. - Random internal audits of =10% of sessions by a senior investigator. - Documentation of any protocol deviations.