Youth Female Cross-Country Skiers Maintain Anaerobic Speed Reserve Classification Across Running and Roller Skiing Modes

Purpose: The anaerobic speed reserve (ASR), defined as the difference between maximal sprint speed (MSS) and maximal aerobic speed (MAS), has been used in track and field to establish locomotor profiles and individualize training. In cross-country (XC) skiing, training encompasses varied activities that involve lower and upper body engagement and present distinct biomechanical and cardiometabolic characteristics. This study aimed to determine whether the locomotor profile of youth XC skiers depends on the locomotion mode. Methods: Twelve regional-level female skiers completed two field performance assessments in running (RUN) and roller skiing (SKI): a half-Cooper 6-minute test to determine MAS and a 40-m sprint to establish MSS. Three profiles (endurance, hybrid, or sprint) were determined from the ASR. Results: MAS was higher in SKI than RUN (17.2 ± 1.24 km·h⁻¹ vs 13.9 ± 1.0 km·h⁻¹; t (11) = 10.19, p < 0.001). MSS was also higher in SKI than RUN (23.0 ± 1.35 km·h⁻¹ vs 20.0 ± 1.3 km·h⁻¹; t (11) = 8.15; p < 0.001). However, the ASR did not significantly differ between modalities (p = 0.606). Most athletes were classified as hybrids in RUN (n = 7) and SKI (n = 6). Conclusion: Our findings indicate that most athletes retain a hybrid profile regardless of the modality, which is probably due to modern XC ski racing requirements. The stability of ASR across modalities suggests that this parameter reflects athlete’s intrinsic characteristics rather than modality-specific demands. The ASR may therefore represent a useful indicator for comparing athletes across different testing modalities.