Torvik Per-Øyvind, Sandbakk Øyvind, van den Tillaar Roland, Talsnes Rune Kjøsen, Danielsen Jørgen
Department of Sports Science and Physical Education, Nord University, Meråker, Norway.
Centre for Elite Sports Research, Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, Trondheim, Norway.
Front Sports Act Living. 2022 Apr 12;4:849731. doi: 10.3389/fspor.2022.849731. eCollection 2022.
The objective of this study was to compare physiological and kinematic responses to double poling (DP) between long-distance (LDS) and all-round (ARS) cross-country skiers.
A number of five world-class LDS (28.8 ± 5.1 years, maximal oxygen uptake (VO): 70.4 ± 2.9 ml·kg·min) and seven ARS (22.3 ± 2.8 years, VO: 69.1 ± 4.2 ml·kg·min) athletes having similar training volumes and VO performed three identical tests; (1) submaximal and incremental tests to exhaustion while treadmill DP to determine gross efficiency (GE), peak oxygen uptake (DP-VO), and peak speed; (2) submaximal and incremental running tests to exhaustion to determine GE, VO (RUN-VO), and peak speed; and (3) an upper-body pull-down exercise to determine one repetition maximum (1RM) and peak power. Physiological responses were determined during both DP and running, together with the assessments of kinematic responses and electromyography (EMG) of selected muscles during DP.
Compared to ARS, LDS reached higher peak speed (22.1 ± 1.0 vs. 20.7 ± 0.9 km·h, = 0.030), DP-VO (68.3 ± 2.1 vs. 65.1 ± 2.7 ml·kg·min, = 0.050), and DP-VO/RUN-VO ratio (97 vs. 94%, = 0.075) during incremental DP to exhaustion, as well as higher GE (17.2 vs. 15.9%, = 0.029) during submaximal DP. There were no significant differences in cycle length or cycle rate between the groups during submaximal DP, although LDS displayed longer relative poling times (~2.4% points) at most speeds compared to ARS ( = 0.015). However, group × speed interaction effects ( < 0.05) were found for pole angle and vertical fluctuation of body center of mass, with LDS maintaining a more upright body position and more vertical pole angles at touchdown and lift-off at faster speeds. ARS displayed slightly higher normalized EMG amplitude than LDS in the muscles rectus abdominis ( = 0.074) and biceps femoris ( = 0.027). LDS performed slightly better on 1RM upper-body strength (122 vs. 114 kg, = 0.198), with no group differences in power in the pull-down exercise.
The combination of better DP-specific aerobic energy delivery capacity, efficiency, and technical solutions seems to contribute to the superior DP performance found among specialized LDS in comparison with ARS.
本研究的目的是比较长距离（LDS）和全能（ARS）越野滑雪运动员对双杖滑雪（DP）的生理和运动学反应。
五名世界级LDS运动员（28.8±5.1岁，最大摄氧量（VO）：70.4±2.9 ml·kg·min）和七名ARS运动员（22.3±2.8岁，VO：69.1±4.2 ml·kg·min），他们的训练量和VO相似，进行了三项相同的测试；（1）在跑步机上进行双杖滑雪至力竭的次最大和递增测试，以确定总效率（GE）、峰值摄氧量（DP-VO）和峰值速度；（2）进行次最大和递增跑步测试至力竭，以确定GE、VO（RUN-VO）和峰值速度；（3）进行上肢下拉运动以确定一次重复最大值（1RM）和峰值功率。在双杖滑雪和跑步过程中均测定生理反应，同时在双杖滑雪过程中评估运动学反应和选定肌肉的肌电图（EMG）。
与ARS相比，LDS在递增双杖滑雪至力竭过程中达到更高的峰值速度（22.1±1.0 vs. 20.7±0.9 km·h，P = 0.030）、DP-VO（68.3±2.1 vs. 65.1±2.7 ml·kg·min，P = 0.050）和DP-VO/RUN-VO比值（97 vs. 94%，P = 0.075），在次最大双杖滑雪过程中GE也更高（17.2 vs. 15.9%，P = 0.029）。在次最大双杖滑雪过程中，两组之间的周期长度或周期速率没有显著差异，尽管与ARS相比，LDS在大多数速度下显示出更长的相对撑杖时间（约2.4个百分点）（P = 0.015）。然而，发现了组×速度交互作用效应（P < 0.05），涉及撑杖角度和身体质心的垂直波动，LDS在更快速度下着陆和离地时保持更直立的身体姿势和更垂直的撑杖角度。在腹直肌（P = 0.074）和股二头肌（P = 0.027）中，ARS显示出略高于LDS的标准化EMG振幅。LDS在1RM上肢力量方面表现略好（122 vs. 114 kg，P = 0.198），在上肢下拉运动中的功率没有组间差异。
与ARS相比，更好的双杖滑雪特定有氧能量输送能力、效率和技术解决方案的结合似乎有助于专业LDS运动员在双杖滑雪中表现更出色。
