Abstract
PURPOSE: To compare physiological responses between a self-paced 4-min double-poling (DP) time-trial (TT(DP)) versus a 4-min diagonal-stride (DS) time-trial (TT(DS)). The relative importance of peak oxygen uptake ([Formula: see text]O(2peak)), anaerobic capacity, and gross efficiency (GE) for projection of 4-min TT(DP) and TT(DS) roller-skiing performances were also examined. METHODS: Sixteen highly trained male cross-country skiers performed, in each sub-technique on separate occasions, an 8 × 4-min incremental submaximal protocol, to assess individual metabolic rate (MR) versus power output (PO) relationships, followed by a 10-min passive break and then the TT(DP) or TT(DS), with a randomized order between sub-techniques. RESULTS: In comparison to TT(DS), the TT(DP) resulted in 10 ± 7% lower total MR, 5 ± 4% lower aerobic MR, 30 ± 37% lower anaerobic MR, and 4.7 ± 1.2 percentage points lower GE, which resulted in a 32 ± 4% lower PO (all P < 0.01). The [Formula: see text]O(2peak) and anaerobic capacity were 4 ± 4% and 30 ± 37% lower, respectively, in DP than DS (both P < 0.01). The PO for the two time-trial (TT) performances were not significantly correlated (R(2) = 0.044). Similar parabolic pacing strategies were used during both TTs. Multivariate data analysis projected TT performance using [Formula: see text]O(2peak), anaerobic capacity, and GE (TT(DP), R(2) = 0.974; TT(DS), R(2) = 0.848). The variable influence on projection values for [Formula: see text]O(2peak), anaerobic capacity, and GE were for TT(DP), 1.12 ± 0.60, 1.01 ± 0.72, and 0.83 ± 0.38, respectively, and TT(DS), 1.22 ± 0.35, 0.93 ± 0.44, and 0.75 ± 0.19, respectively. CONCLUSIONS: The results show that a cross-country skier's "metabolic profile" and performance capability are highly sub-technique specific and that 4-min TT performance is differentiated by physiological factors, such as [Formula: see text]O(2peak), anaerobic capacity, and GE.