Centre for Elite Sports Research, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway.
Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Torino, Italy.
PLoS One. 2018 May 23;13(5):e0197592. doi: 10.1371/journal.pone.0197592. eCollection 2018.
The purpose of the present study was to examine the influence of increased loading of the roller ski on metabolic cost, gross efficiency, and kinematics of roller ski skating in steep and moderate terrain, while employing two incline-specific techniques. Ten nationally ranked male cross-country skiers were subjected to four 7-minute submaximal intervals, with 0, 0.5, 1.0, and 1.5 kg added beneath the roller-ski in a randomized order. This was done on two separate days, with the G2 skating at 12% incline and 7 km/h speed and G3 skating at 5% incline and 14 km/h speed, respectively. At 12% incline, there was a significant increase in metabolic rate and a decrease in gross efficiency with added weight (P<0.001 and P = 0.002). At 5% incline, no change in metabolic rate or gross efficiency was found (P = 0.89 and P = 0.11). Rating of perceived exertion (RPE) increased gradually with added weight at both inclines (P>0.05). No changes in cycle characteristics were observed between the different ski loadings at either incline, although the lateral and vertical displacements of the foot/skis were slightly altered at 12% incline with added weight. In conclusion, the present study demonstrates that increased loading of the ski increases the metabolic cost and reduces gross efficiency during steep uphill roller skiing in G2 skating, whereas no significant effect was revealed when skating on relatively flat terrain in G3. Cycle characteristics remained unchanged across conditions at both inclines, whereas small adjustments in the displacement of the foot coincided with the efficiency changes in uphill terrain. The increased RPE values with added ski-weight at both inclines indicates that other factors than those measured here could have influenced effort and/or fatigue when lifting a heavier ski.
本研究的目的是探讨在采用两种特定坡度技术的情况下，增加滚轮滑雪的负荷对陡峭和中等地形的滚轮滑雪代谢成本、总效率和运动学的影响。10 名国家级男子越野滑雪运动员分别在两天内进行了 4 次 7 分钟的次最大强度间歇，随机在滚轮滑雪板下增加 0、0.5、1.0 和 1.5 公斤。G2 滑雪的坡度为 12%，速度为 7 公里/小时，G3 滑雪的坡度为 5%，速度为 14 公里/小时。在 12%的坡度下，随着重量的增加，代谢率显著增加，总效率降低（P<0.001 和 P = 0.002）。在 5%的坡度下，代谢率或总效率没有变化（P = 0.89 和 P = 0.11）。在两个坡度下，随着重量的增加，感觉用力程度（RPE）逐渐增加（P>0.05）。在两种坡度下，不同滑雪负荷之间的周期特征没有变化，尽管在 12%的坡度下，随着重量的增加，脚/滑雪板的侧向和垂直位移略有改变。总之，本研究表明，在 G2 滑雪的陡峭上坡时，增加滑雪板的负荷会增加代谢成本并降低总效率，而在 G3 较平坦的地形上滑雪时则没有显著影响。在两个坡度下，条件不变时，周期特征保持不变，而脚的位移略有调整，与上坡时的效率变化相吻合。在两个坡度下，随着滑雪板重量的增加，RPE 值增加，这表明在抬起较重的滑雪板时，除了这里测量的因素之外，其他因素可能会影响努力程度和/或疲劳程度。
