Day-To-Day Endurance Training Periodization of World-Class Cross-Country Skiers

Abstract

This study aimed to investigate the day-to-day endurance training periodization of male and female world-class cross-country skiers. Self-reported session-by-session training data from 17 (7 female) world-class cross-country skiers were retrospectively analyzed. The data were separated into general preparation (GP) and competition periods (CP), during which all skiers achieved world-class performance. Daily training volume was categorized as very low (0%–50% of mean daily volume), low (50%–100%), moderate (100%–150%), and high (≥ 150%). Training load (Training Impulse, TRIMP) was calculated as the product of duration and an intensity factor of 1, 2, or 3 for low-, moderate-, and high-intensity training, respectively. Training volume was distributed as 18%/22%/32%/28% across very low/low/moderate/high volume days during GP, whereas the corresponding distribution during CP was 23%/35%/32%/10%. Shifts in daily TRIMP from GP to CP mirrored changes in training volume. During GP, the acute-to-chronic work ratio (ACWR) was 0.75–1.25 on 69% of the days, with 13% of the days showing lower ratios and 18% higher. During CP, the corresponding values were 69%/19%/12%. Intensive sessions occurred every 3.6 ± 0.3 days during GP compared to every 3.0 ± 0.3 days during CP. Training volumes on the day before intensive sessions were 127 ± 13% (GP) and 99 ± 7% (CP) of the daily mean, whereas the corresponding values for the days after were 116 ± 8% and 87 ± 9%. These data provide new insights into day-to-day periodization in world-class cross-country skiers, highlighting the sequential application of training loads by alternating training days of high volume, elevated intensity every 3–4 days, or reduced training load or rest every 8–9 days, while only 5% combining volume and intensity.