Author(s): HE, Z., HE, Y., Institution: CHINA INSTITUTE OF SPORT SCIENCE, Country: CHINA, Abstract-ID: 701

INTRODUCTION:
To identify phase-specific and cumulative multi-system adaptations during stepped altitude training in elite race walkers, and to determine performance-related monitoring markers supporting individualized altitude training regulation.
METHODS:
Ten national-level race walkers completed an 18-week stepped altitude training program including a moderate-altitude adaptation phase (1800 m), a sub-altitude intensification phase (2500 m), and a pre-competition adjustment phase (1800 m). Blood, urine, rating of perceived exertion (RPE), body composition, dietary intake, and training load were assessed at 11 predefined time points. Relative longitudinal changes (percent) in physiological markers were analyzed as predictors of performance improvement rate (percent) using Spearman correlation.
RESULTS:
Adaptation responses showed clear phase dependency. During the initial 1800 m phase, immune mobilization and stress regulation were primary determinants, with lymphocyte proportion and inflammatory ratios (NLR, PLR) associated with performance improvement. During the 2500 m phase, adaptation shifted from erythrocyte quantity toward functional quality and oxygen transport efficiency, reflected by mean corpuscular hemoglobin concentration, hemoglobin density indices, and hypothalamic-pituitary-adrenal axis activation. Vitamin D2 and B-vitamin markers were positively associated with performance during mid-to-late altitude exposure. After return to 1800 m, hematological variables stabilized, and pre-competition performance was characterized by secondary reticulocyte activation, controlled inflammatory status, and low cumulative creatine kinase responses. Non-blood measures showed inverse associations between RPE variability and performance improvement, greater body mass stability in better responders, and positive associations between late-phase carbohydrate intake adjustment and performance gains. Urinary markers indicated that early optimal hydration and consistently low renal stress were linked to superior adaptation quality.
CONCLUSION:
Performance enhancement during stepped altitude training in elite race walking results from a coordinated multi-system adaptive process integrating immune regulation, stress control, erythrocyte functional optimization, nutritional support, and fatigue management rather than isolated erythropoietic augmentation. Superior performance outcomes are associated with achieving effective physiological mobilization at lower systemic cost, providing a framework for precision monitoring and individualized altitude training strategies.