Holmberg Hans-Christer, Lindinger Stefan, Stöggl Thomas, Björklund Glenn, Müller Erich
Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
Med Sci Sports Exerc. 2006 Oct;38(10):1853-60. doi: 10.1249/01.mss.0000230121.83641.d1.
In the classical style of cross-country skiing, the double-poling (DP) technique, which is regarded as an upper-body exercise, is used on the flatter parts of a course. Limited biomechanical and physiological data are available about DP compared with other cross-country skiing techniques. The purpose of the present study was to evaluate the possible role of the lower body during DP.
Eleven elite cross-country skiers performed two incremental tests using DP roller skiing at 1 degree inclination on a treadmill with or without locking the knee and ankle joints (DPLOCKED and DPFREE). Maximal and peak oxygen uptake (VO2max and VO2peak) during classic diagonal skiing and DP, respectively, were measured. In addition, heart rate, blood lactate concentration, and maximal DP velocity (Vmax) were determined. Pole-ground reaction forces and joint angles (elbow, hip, knee, and ankle) were analyzed.
The skiers obtained 7.7% higher VO2peak, 9.4% higher Vmax, and 11.7% longer time to exhaustion during DPFREE compared with DPLOCKED (all P < 0.05). There was a higher heart rate and blood lactate concentration in DPLOCKED at submaximal stages (all P < 0.05), with no difference in oxygen consumption. At 85% Vmax, corresponding to approximately 81% VO2peak FREE, the differences in physiological variables were accompanied by a 13.6% higher poling frequency, a 4.9% shorter poling phase, 13.3% shorter recovery phase, and 10.9% lower relative pole force in DPLOCKED (all P < 0.05).
Movements of the knee and ankle joints are an integrative part in the skillful use of the DP technique, and restriction of the motion in these joints markedly affects both biomechanical and physiological variables, impairing DP performance.
在传统越野滑雪风格中，双杖滑雪（DP）技术被视为一种上身运动，用于赛道较平坦的部分。与其他越野滑雪技术相比，关于DP的生物力学和生理学数据有限。本研究的目的是评估下肢在DP过程中可能发挥的作用。
11名精英越野滑雪运动员在跑步机上以1度倾斜度进行DP轮滑滑雪，进行了两项递增测试，分别是锁定膝关节和踝关节（DPLOCKED）和不锁定（DPFREE）的情况。分别测量了传统对角滑雪和DP过程中的最大摄氧量和峰值摄氧量（VO2max和VO2peak）。此外，还测定了心率、血乳酸浓度和最大DP速度（Vmax）。分析了杖地反作用力和关节角度（肘部、髋部、膝部和踝部）。
与DPLOCKED相比，滑雪者在DPFREE状态下VO2peak高7.7%，Vmax高9.4%，力竭时间长11.7%（所有P<0.05）。在次最大强度阶段，DPLOCKED的心率和血乳酸浓度较高（所有P<0.05），耗氧量无差异。在85%Vmax时，对应于约81%VO2peak FREE，生理变量的差异伴随着DPLOCKED中杖击频率高13.6%、杖击阶段短4.9%、恢复阶段短13.3%和相对杖力低10.9%（所有P<0.05）。
膝关节和踝关节的运动是熟练运用DP技术的一个组成部分，限制这些关节的运动明显影响生物力学和生理变量，损害DP表现。
