The Influence of Pole Length on Performance, O2 Cost, and Kinematics in Double Poling

In the double-poling (DP) cross-country-skiing technique, propulsive forces are transferred solely through the poles. The aim of the current study was to investigate how pole length influences DP performance, O-2 cost, and kinematics during treadmill roller skiing. Methods: Nine male competitive cross-country skiers (24 +/- 3 y, 180 +/- 5 cm, 72 +/- 5 kg, VO(2)max running 76 6 mL . kg(-1) . min(-1)) completed 2 identical test protocols using self-selected (84% +/- 1% of body height) and long poles (self-selected + 7.5 cm; 88% +/- 1% of body height) in a counterbalanced fashion. Each test protocol included a 5-min warm-up (2.5 m/s; 2.5 degrees) and three 5-min submaximal sessions (3.0, 3.5, and 4.0 m/s; 2.5 degrees) for assessment of O-2 cost, followed by a self-paced 1000-m time trial (similar to 3 min, >5.0 m/s; 2.5 degrees). Temporal patterns and kinematics were assessed using accelerometers and 2D video. Results: Long poles reduced 1000-m time (mean 90% confidence interval; -1.0% 0.7%, P = .054) and submaximal O-2 cost (-2.7% +/- 1.0%, P = .002) compared with self-selected poles. The center-of-mass (CoM) vertical range of displacement tended to be smaller for long than for self-selected poles (23.3 +/- 3.0 vs 24.3 +/- 3.0 cm, P = .07). Cycle and reposition time did not differ between pole lengths at any speeds tested, whereas poling time tended to be shorter for self-selected than for long poles at the lower speeds (<= 3.5 m/s, P <=.10) but not at the higher speeds (>= 4.0 m/s, P >= .23). Conclusion: DP 1000-m time, submaxinial O-2 cost, and CoM vertical range of displacement were reduced in competitive cross-country skiers using poles 7.5 cm longer than self-selected ones.