Force-time metric responses to training in an Olympic 400m sprinter across a two-week microcycle: a case study

Given the underrepresentation of female athletes in the scientific literature, this study investigated changes in neuromuscular performance across a two-week training microcycle in a world-class 400 m sprinter. The microcycle included resistance training, sprint speed, speed endurance, pace endurance, and resisted sprinting. Neuromuscular performance was assessed pre-post-practice using a countermovement vertical jump (CMJ) performed on a portable force plate system sampling at 1000 Hz (Hawkin Dynamics). Meaningful changes in performance were defined as values exceeding one standard deviation from baseline, established from 30 testing sessions conducted in the six months preceding the monitored microcycle. The results demonstrated clear acute post-practice alterations in neuromuscular function, with force and power-producing capacities declining in both the braking and propulsive phases of the CMJ immediately after practice, accompanied by reductions in jump height and reactive strength index-modified, particularly following sprint speed and endurance-based training sessions. These decrements were transient, with notable increases observed after rest days, suggesting a return toward or above the athlete's established baseline range. Overall, the observed performance fluctuations occurred alongside a periodized sequence of training and recovery days, illustrating the potential value of CMJ monitoring for tracking changes in performance across a training microcycle.