Competitive cross-country skiers have a longer time to exhaustion and a larger accumulation of oxygen deficit than recreational cross-country skiers during an intermittent interval protocol standardized for maximal aerobic power

Abstract

Purpose: To compare a competitive and a recreational group of cross-country (XC) skiers in time to exhaustion (𝑇𝑇𝐸) and accumulation of oxygen deficit (𝑂2 𝑑𝑒𝑓) in an intermittent interval protocol standardized for maximal aerobic power (𝑀𝐴𝑃).

Methods: Twenty-two male XC skiers were recruited for the study and assigned into a competitive (𝑛 = 12) and a recreational (𝑛 = 10) group of similar age, weight, and height. All protocols were performed using the V2 ski skating sub-technique with roller skis on a treadmill. First, they performed two baseline protocols (sub-maximal loads and 1000-meter time-trial (TT)), to quantify 𝑀𝐴𝑃 and maximal accumulation of oxygen deficit (𝑀𝐴𝑂𝐷). After a 60-minute break, they performed an intermittent interval protocol individually tailored to each subject’s 𝑀𝐴𝑃. The test consisted of two phases repeating in cycles; a recovery phase lasting 20 seconds at 60% 𝑀𝐴𝑃, followed by a work phase at 120% 𝑀𝐴𝑃 lasting 40 seconds, resulting in each cycle averaging an intensity of 100% 𝑀𝐴𝑃. 𝑇𝑇𝐸 was measured along with oxygen consumption (𝑉 𝑂2) and Σ 𝑂2 𝑑𝑒𝑓.

Results: The competitive group was faster during the 1000-meter TT and had a higher maximal rate of oxygen consumption (𝑉 𝑂2𝑚𝑎𝑥), gross efficiency (𝐺𝐸) and 𝑀𝐴𝑃 than the recreational group. 𝑀𝐴𝑂𝐷 was, however, similar for both groups. During the interval protocol, the competitive group had a 34 [3, 65] % longer 𝑇𝑇𝐸 (473 ± 141 vs. 353 ± 94 s, p = 0.032), and accumulated a 45 [22, 68] % larger 𝑂2 𝑑𝑒𝑓 (112 ± 18 vs. 77 ± 20 %𝑀𝐴𝑂𝐷, p = 0.001) than the recreational group.

Conclusion: The competitive group had a longer 𝑇𝑇𝐸 and a larger Σ 𝑂2 𝑑𝑒𝑓 than the recreational group during an intermittent interval protocol standardized for 𝑀𝐴𝑃. This implies that 𝑇𝑇𝐸 could be related to the ability to repeatedly accumulate smaller bulks of 𝑂2 𝑑𝑒𝑓 amounting to a large total.