Andersson Erik, Holmberg Hans-Christer, Ørtenblad Niels, Björklund Glenn
1Department of Health Sciences, Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, SWEDEN; 2Swedish Olympic Committee, Stockholm, SWEDEN; and 3Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster, University of Southern Denmark, Odense, DENMARK.
Med Sci Sports Exerc. 2016 Dec;48(12):2544-2554. doi: 10.1249/MSS.0000000000001037.
This study aimed to examine the metabolic responses and pacing strategies during the performance of successive sprint time trials (STTs) in cross-country skiing.
Ten well-trained male cross-country skiers performed four self-paced 1300-m STTs on a treadmill, each separated by 45 min of recovery. The simulated sprint time trial (STT) course was divided into three flat (1°) sections (S1, S3, and S5) involving the double poling subtechnique interspersed with two uphill (7°) sections (S2 and S4) involving the diagonal stride subtechnique. Treadmill velocity and V˙O2 were monitored continuously, and gross efficiency was used to estimate the anaerobic energy supply.
The individual trial-to-trial variability in STTs performance time was 1.3%, where variations in O2 deficit and V˙O2 explained 69% (P < 0.05) and 11% (P > 0.05) of the variation in performance. The first and the last STTs were equally fast (228 ± 10 s) and 1.3% faster than the second and the third STTs (P < 0.05). These two fastest STTs were associated with a 14% greater O2 deficit (P < 0.05), whereas the average V˙O2 was similar during all four STTs (86% ± 3% of V˙O2max). Positive pacing was used throughout all STTs, with significantly less time spent on the first than second course half. In addition, metabolic rates were substantially higher (30%) for uphill than for flat skiing, indicating that pacing was regulated to the terrain.
The fastest STTs were characterized primarily by a greater anaerobic energy production, which also explained 69% of the individual variation in performance. Moreover, the skiers used positive pacing and a variable exercise intensity according to the course profile, yielding an irregular distribution of anaerobic energy production.
本研究旨在探讨越野滑雪连续冲刺计时赛（STT）过程中的代谢反应和配速策略。
10名训练有素的男性越野滑雪运动员在跑步机上进行4次自定节奏的1300米STT，每次之间有45分钟的恢复时间。模拟的冲刺计时赛（STT）赛道分为三个平坦（1°）路段（S1、S3和S5），采用双杖滑雪子技术，其间穿插两个上坡（7°）路段（S2和S4），采用斜向跨步滑雪子技术。持续监测跑步机速度和V˙O2，并使用总效率来估计无氧能量供应。
STT成绩时间的个体间试验变异性为1.3%，其中氧亏和V˙O2的变化分别解释了成绩变化的69%（P<0.05）和11%（P>0.05）。第一次和最后一次STT速度相同（228±10秒），比第二次和第三次STT快约1.3%（P<0.05）。这两次最快的STT与氧亏增加14%相关（P<0.05），而在所有四次STT中平均V˙O2相似（为V˙O2max的86%±3%）。在所有STT中均采用了积极配速，第一段赛程所用时间明显少于后半段赛程。此外，上坡时的代谢率比平地滑雪时高得多（约30%），这表明配速是根据地形进行调节的。
最快的STT主要特征是无氧能量产生增加，这也解释了69%的个体成绩差异。此外，滑雪者根据赛道情况采用积极配速和可变运动强度，导致无氧能量产生分布不均。
