Changes in energy system contributions to the Wingate anaerobic test in climbers after a high altitude expedition

Purpose: The Wingate anaerobic test measures the maximum anaerobic capacity of the lower limbs. The energy sources of Wingate test are dominated by anaerobic metabolism (~ 80%). Chronic high altitude exposure induces adaptations on skeletal muscle function and metabolism. Therefore, the study aim was to investigate possible changes in the energy system contribution to Wingate test before and after a high-altitude sojourn. Methods: Seven male climbers performed a Wingate test before and after a 43-day expedition in the Himalaya (23 days above 5.000 m). Mechanical parameters included: peak power (PP), average power (AP), minimum power (MP) and fatigue index (FI). The metabolic equivalents were calculated as aerobic contribution from O₂ uptake during the 30-s exercise phase (W_VO2), lactic and alactic anaerobic energy sources were determined from net lactate production (W_La) and the fast component of the kinetics of post-exercise oxygen uptake (W_PCr), respectively. The total metabolic work (W_TOT) was calculated as the sum of the three energy sources. Results: PP and AP decreased from 7.3 ± 1.1 to 6.7 ± 1.1 W/kg and from 5.9 ± 0.7 to 5.4 ± 0.8 W/kg, respectively, while FI was unchanged. W_TOT declined from 103.9 ± 28.7 to 83.8 ± 17.8 kJ. Relative aerobic contribution remained unchanged (19.9 ± 4.8% vs 18.3 ± 2.3%), while anaerobic lactic and alactic contributions decreased from 48.3 ± 11.7 to 43.1 ± 8.9% and increased from 31.8 ± 14.5 to 38.6 ± 7.4%, respectively. Conclusion: Chronic high altitude exposure induced a reduction in both mechanical and metabolic parameters of Wingate test. The anaerobic alactic relative contribution increased while the anaerobic lactic decreased, leaving unaffected the overall relative anaerobic contribution to Wingate test.