Dept. of Human Movement Science, Norwegian University of Science and Technology, Trondheim, Norway.
Int J Sports Physiol Perform. 2014 Jan;9(1):19-24. doi: 10.1123/ijspp.2013-0344. Epub 2013 Aug 26.
This study investigated changes in technique and efficiency after high-intensity exercise to exhaustion in elite cross-country skiers. Twelve elite male skiers completed 4 min submaximal exercise before and after a high-intensity incremental test to exhaustion with the G3 skating technique on a 5% inclined roller-ski treadmill. Kinematics and kinetics were monitored by instrumented roller skis, work rate was calculated as power against roller friction and gravity, aerobic metabolic cost was determined from gas exchange, and blood lactate values indicated the anaerobic contribution. Gross efficiency was the work rate divided by aerobic metabolic rate. A recovery period of 10 min between the incremental test and the posttest was included to allow the metabolic values to return to baseline. Changes in neuromuscular fatigue in upper and lower limbs before and after the incremental test were indicated by peak power in concentric bench press and squat-jump height. From pretest to posttest, cycle length decreased and cycle rate increased by approximately 5% (P < 0.001), whereas the amount of ski forces did not change significantly. Oxygen uptake increased by 4%, and gross efficiency decreased from 15.5% ± 0.7% to 15.2% ± 0.5% from pretest to posttest (both P < .02). Correspondingly, blood lactate concentration increased from 2.4 ± 1.0 to 6.2 ± 2.5 mmol/L (P < .001). Bench-press and squat-jump performance remained unaltered. Elite cross-country skiers demonstrated a less efficient technique and shorter cycle length during submaximal roller-ski skating after high-intensity exercise. However, there were no changes in ski forces or peak power in the upper and lower limbs that could explain these differences.
本研究调查了在高强度至力竭的越野滑雪精英运动员中，经过高负荷运动后技术和效率的变化。12 名男性精英滑雪运动员在 5%倾斜的滚轴滑雪跑步机上使用 G3 滑冰技术完成 4 分钟的亚最大强度运动后，进行了高强度递增至力竭的测试。运动学和动力学通过仪器化的滚轴滑雪板进行监测，工作率通过功率除以滚轴摩擦力和重力进行计算，有氧代谢成本通过气体交换确定，血乳酸值表示无氧贡献。总效率是工作率除以有氧代谢率。递增测试和后测试之间包括 10 分钟的恢复期，以使代谢值恢复到基线。通过在递增测试前后的同心台式压力机和深蹲跳跃高度的峰值功率来指示上下肢的神经肌肉疲劳变化。从预测试到后测试，周期长度减少了约 5%，周期率增加了约 5%（P < 0.001），而滑雪力的大小没有明显变化。耗氧量增加了 4%，总效率从预测试的 15.5%±0.7%降至后测试的 15.2%±0.5%（均 P < 0.02）。相应地，血乳酸浓度从 2.4±1.0mmol/L 增加到 6.2±2.5mmol/L（P < 0.001）。台式压力机和深蹲跳跃的表现保持不变。在高强度运动后进行的亚最大强度滚轴滑雪运动中，越野滑雪精英运动员的技术效率较低，周期长度较短。然而，上下肢的滑雪力或峰值功率没有变化，无法解释这些差异。
