Int J Sports Physiol Perform. 2020 Apr 3;15(6):884-891. doi: 10.1123/ijspp.2019-0310. Print 2020 Jul 1.
To investigate how self-selected pole length (PL) of ∼84% (PL84%) compared with ∼90% (PL90%) of body height influenced performance during a 700-m time trial with undulating terrain on snow.
Twenty-one cross-country skiers, 7 of whom were women, performed 4 trials at a maximal effort in a counterbalanced fashion with PL84% and PL90% separated by 20-minute breaks between trials. In trials I and II, only double poling was allowed, while in trials III and IV, skiers used self-selected classical subtechniques. Continuous speed, cyclic parameters, and heart rate were collected using microsensors in addition to a post-time-trial rating of perceived exertion (RPE).
The 700-m times with only double poling were significantly shorter with PL90% than PL84% (mean ± 95% confidence limits -1.6% ± 1.0%). Segment analyses showed higher speed with PL90% in uphill sections than with PL84% (3.7% ± 2.1%), with the greatest difference found for the female skiers (5.6% ± 2.9%). In contrast, on flat terrain at high skiing speeds, speed was reduced with PL90% compared with PL84% (-1.5% ± 1.4%); this was only significant for the male skiers. During free choice of classical subtechniques, PL did not influence performance in any segments, choice of subtechnique, or cycle rate during the trials. No differences in rating of perceived exertion or heart rate between PLs were found.
PL90% improved performance in uphills at low speeds when using double poling but hindered performance on flat terrain and at higher speeds compared with self-selected PLs. Choice of PL should, therefore, be based on racecourse topography, preferred subtechniques, and the skier's physiological and technical abilities.
研究自我选择的滑雪杖长度(PL)约 84%(PL84%)与约 90%(PL90%)的身高相比如何影响在雪地上有起伏地形的 700 米计时赛中的表现。
21 名越野滑雪运动员,其中 7 名为女性,以 20 分钟的间隔在相反的方式下进行 4 次最大努力的试验,试验中分别使用 PL84%和 PL90%。在试验 I 和 II 中,只允许使用双杖,而在试验 III 和 IV 中,滑雪者使用自我选择的古典副技术。除了赛后的感知用力评估(RPE)外,使用微传感器收集连续速度、循环参数和心率。
仅使用双杖的 700 米时间,PL90%比 PL84%明显缩短(平均±95%置信区间-1.6%±1.0%)。分段分析显示,在上坡段,PL90%的速度高于 PL84%(3.7%±2.1%),女性滑雪者的差异最大(5.6%±2.9%)。相比之下,在高速平地上,PL90%的速度比 PL84%降低(-1.5%±1.4%);这仅对男性滑雪者有显著影响。在自由选择古典副技术的试验中,PL 对任何分段、副技术选择或周期率都没有影响。在 PL 之间,感知用力或心率没有差异。
PL90%在使用双杖的低速上坡时提高了表现,但与自我选择的 PL 相比,在平地和更高速度时会阻碍表现。因此,PL 的选择应基于赛道地形、首选副技术以及滑雪者的生理和技术能力。