Criteria for the functional and metabolic support of the adaptation of the body of ski racers to the training loads of the preparatory period

Abstract

Introduction. Functional and metabolic assessment of adaptive-compensatory reactions underlying physical performance in humans, particularly athletes, is a pressing issue in physiology. Aims. This paper aims to identify markers of functional metabolic adaptation in cross-country skiers to training loads in the preparatory period. Materials and methods. The study involved qualified male cross-country skiers aged 19–23 years, divided into leaders (n = 10) and reserve athletes (n = 10) based on average speed (km/h) at Stage 5 during ski ergometer testing. Body composition, blood parameters, hemodynamics, respiratory function, and heart rate variability were assessed. A database of 62 parameters was created from the results. Statistical analysis was performed using IBM SPSS Statistics v. 23, and Spearman’s rank correlation coefficient was calculated. Materials and methods. New indices and an RMSSD-based measure of parasympathetic functional reserve (IPVNS) were proposed as prognostic criteria for performance in cross-country skiers. The determinants of RMSSD and the contributions of different physiological systems to heart rate regulation were identified. Leaders demonstrated a physiologically adequate shift from systemic vagal regulation to a local, cell-mediated type of adaptive regulation. Reserve athletes exhibited dominance of systemic cholinergic regulation at all stages. These findings confirm that high RMSSD values cannot be unambiguously interpreted as a criterion of optimal adaptation and high performance in cross-country skiers.
Conclusion. Factor and regression analysis of 62 physiological and metabolic parameters in qualified cross-country skiers revealed RMSSD as a predictor of training-induced adaptation, as well as physical performance criteria specific to leader and reserve athletes at each stage of the preparatory period