Tolerance to chronic neuromuscular fatigue during a training microcycle in a European Rugby Team

The aim of this study was to analyze the chronic neuromuscular fatigue over the course of training microcycle (one week) in 27 rugby players, differentiating between professional ( n = 10) and non-professional ( n = 17) athletes from the same team, as well as considering training load distribution and playing positions. A retrospective observational study was conducted, in which participants performed countermovement jumps (CMJ) before and after training sessions using a Chronojump Boscosystem contact platform. A total of 464 jumps were analyzed (234 pre- and 230 post-training), recording metrics such as jump height, flight time, average propulsive power, and initial velocity. Professional players showed higher values in jump height (39.36± 4.24 cm), average power (1348.34±149,72 W) as well as a better reactive strength index (0.57), compared to non-professionals, who exhibited accumulated reductions in jump height (35,32± 6.80 cm), power (1176,62±26,96 W), and initial velocity (2,65±0,26 m/s) throughout the microcycle, indicating greater neuromuscular fatigue. Regarding playing positions, front-row players demonstrated lower average jump height (34.95±7,97 cm), while backline players stood out for higher speed (2.823±0,15 m/s) and power for back row (1381.92±171,87 W). A positive effect of gym-based activation exercises prior to field training was observed, associated with improvements in jump height (38.62±6,07 cm vs. 36.31±6,05 cm; F = 14.8; p < 0.01; SE=0.03) power (1298.48±203,3 W vs. 1231.26±166,47 W), and initial velocity (2.75±025 m/s vs. 2.66±0,22 m/s). suggesting a post-activation potentiation (PAP) effect that could temporarily enhance neuromuscular performance. Therefore, incorporating PAP protocols before field sessions may be an effective strategy to optimize athletes' physical performance.