What is the optimal classical style sub-technique during uphill roller skiing in elite male cross-country skiers?

PURPOSE: To compare performance, physiological and biomechanical responses between double poling (DP) and diagonal stride (DIA) during treadmill roller skiing in elite male cross-country skiers. METHOD: Twelve skiers (VO(2peak) DIA(up); 74.7 ± 3.7 ml kg(−1) min(−1)) performed two DP conditions at 1° (DP(flat)) and 8° (DP(up)) incline, and one DIA condition, 8° (DIA(up)). Submaximal gross efficiency (GE) and maximal 3.5 min time-trial (TT) performance, including measurements of VO(2peak) and maximal accumulated O(2)-deficit (MAOD), were determined. Temporal patterns and kinematics were assessed using 2D video, while pole kinetics were obtained from pole force. RESULTS: DIA(up) induced (mean, [95% confidence interval]) 13% [4, 22] better 3.5-min TT performance, 7%, [5, 10]) higher VO(2peak) and 3% points [1, 5] higher GE compared to DP(up) (all P < 0.05). DP(up) induced 120% higher MAOD compared to DP(flat), while no significant differences were observed for VO(2peak) or GE between DP(flat) and DP(up). There was a large correlation between performance and GE in DP and a large correlation between performance and VO(2peak) for DIA(up) (all r = 0.7–0.8, P < 0.05). No correlations were found between performance and VO(2peak) for any of the DP conditions, nor between performance and GE for DIA(up) (r = 0.0–0.2, P > 0.1). CONCLUSION: At 8º uphill roller skiing, DIA(up) induce higher VO(2peak), GE, and superior time-trial performance than DP(up) in elite male skiers. There was no difference between VO(2peak) or GE between DP(flat) and DP(up). A large correlation was observed between DIA(up) performance and DIA(up) VO(2peak), while DP performance was best correlated to submaximal GE.