Comparative analysis of running power and heart rate responses in elite male orienteers during national and european sprint championships

Abstract

Sprint orienteering requires the integration of high-intensity running with continuous technical decision-making, yet little is known about second-by-second mechanical and physiological responses during elite competition. This study compared external (running power) and internal (heart rate) load characteristics of two elite male orienteers across three sprint races: the Bulgarian National Sprint Championships and two European Orienteering Championship events (Sprint Qualification and Knock-Out (KO) Sprint Qualification). Second-bysecond running power (Stryd) and heart rate (Suunto chest strap) data were analysed using time-aware segmentation based on official race durations. Variables included mean power, peak 5 s/30 s/60 s power, power variability (CV%), mean heart rate, %HRmax (based on laboratory-verified HRmax), time spent >90% HRmax, pacing indices, HR drift and power–HR decoupling. Mean running power was higher in international competitions for both athletes, particularly in the KO Sprint format, reflecting the influence of shorter race duration and higher mechanical intensity demands. However, physiological responses were athlete-specific: one athlete demonstrated greater cardiovascular strain during European events (~96% HRmax; >95% time >90% HRmax), whereas the other exhibited the highest relative strain during the national competition (~95% HRmax). Differences were also evident in pacing structure, with one athlete showing consistent positive pacing and stable HR responses, while the other demonstrated more variable pacing and greater cardiovascular drift during international races. These findings indicate that sprint orienteering performance is characterised by sustained near-maximal aerobic intensity combined with repeated supramaximal mechanical bursts, whereas physiological load is strongly athlete-specific and not determined by competition level alone. The results support the value of integrated internal–external load monitoring for individualised performance profiling and competition preparation in elite sprint orienteering.