Competitive Cross-Country Skiers Have Longer Time to Exhaustion Than Recreational Cross-Country Skiers During Intermittent Work Intervals Normalized to Their Maximal Aerobic Power
Purpose: To investigate differences in time to exhaustion (TTE), O2 uptake (˙VO2), and accumulated O2 deficit (Odef2) between competitive and recreational cross-country (XC) skiers during an intermittent-interval protocol standardized for maximal aerobic power (MAP). Methods: Twelve competitive (maximal ˙VO2 [˙VO2max]=76.5±3.8mL⋅kg−1⋅min−1) and 10 recreational (˙VO2max=63.5±6.3mL⋅kg−1⋅min−1) male XC skiers participated. All tests were performed on a rollerski treadmill in the V2 ski-skating technique. To quantify MAP and maximal accumulated oxygen deficit (MAOD), the skiers performed a steady-state submaximal test followed by a 1000-m time trial. After a 60-minute break, TTE, ˙VO2, and accumulated Odef2 were measured during an intermittent-interval protocol (40-s work and 20-s recovery), which was individually tailored to 120% and 60% of each subject’s MAP. Results: During the 1000-m time trial, the competitive skiers had 21% (95% CI, 12%–30%) shorter finish time and 24% (95% CI, 14%–34%) higher MAP (all P < .01) than the recreational skiers. No difference was observed in relative exercise intensity (average power/MAP; P = .28), MAOD (P = .18), or fractional utilization of ˙VO2max. During the intermittent-interval protocol, the competitive skiers had 34% (95% CI, 3%–65%) longer TTE (P = .03) and accumulated 61% (95% CI, 27%–95%) more Odef2 (P = .001) than the recreational skiers during work phases. Conclusions: Competitive XC skiers have longer TTE and accumulate more Odef2 than recreational XC skiers during an intermittent-interval protocol at similar intensity relative to MAP. This implies that performance in intermittent endurance sports is related to the ability to repeatedly recharge fractions of MAOD.
Published in International Journal of Sports Physiology and Performance (IJSPP), 2023
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