Mechanical efficiency and neuromuscular regulation in elite sprint orienteering: A high-resolution competition case analysis

Sprint orienteering requires rapid accelerations, repeated directional changes, and sustained high-intensity locomotion under cognitive load, yet mechanical efficiency and neuromuscular regulation during elite competition remain insufficiently explored. The aim of this study was to examine mechanical efficiency and neuromuscular regulation in elite sprint orienteering across different competition contexts. A high-resolution case-study design was applied, analyzing second-by-second wearable biomechanical data from two elite male orienteers across three sprint competitions each (national and European Championship events). Descriptive statistical analysis was performed, including mean ± standard deviation calculations, coefficient of variation, and Pearson correlation analysis. International races, particularly the Knock-Out Sprint format, were characterized by shorter ground contact times in both athletes (e.g., 225.7 ± 34.8 ms to 210.9 ± 21.3 ms in athlete 1), indicating enhanced reactive force application. Leg spring stiffness remained relatively stable across competitions (~8.3-8.4 in athlete 1 and ~9.3-9.5 in athlete 2), suggesting preserved elastic energy regulation despite reduced contact time. Substantial inter-individual differences were observed in mechanical variability (GCT CV ~10-15% vs. ~30-35%) and power-stiffness coupling (r = 0.07-0.65), reflecting divergent neuromuscular strategies under competitive stress. These findings indicate that sprint orienteering performance is influenced not only by physiological intensity but also by fatigue-related mechanical regulation. The small sample size and reliance on wearable-derived estimates limit generalizability. Practically, high-resolution biomechanical monitoring may support individualized performance profiling and training prescription. The originality of this study lies in its second-by-second competition analysis of mechanical efficiency in elite sprint orienteering.