Coyle E F, Feltner M E, Kautz S A, Hamilton M T, Montain S J, Baylor A M, Abraham L D, Petrek G W
Department of Kinesiology and Health Education, University of Texas, Austin 78712.
Med Sci Sports Exerc. 1991 Jan;23(1):93-107.
In this study we evaluated the physiological and biomechanical responses of "elite-national class" (i.e., group 1; N = 9) and "good-state class" (i.e., group 2; N = 6) cyclists while they simulated a 40 km time-trial in the laboratory by cycling on an ergometer for 1 h at their highest power output. Actual road racing 40 km time-trial performance was highly correlated with average absolute power during the 1 h laboratory performance test (r = -0.88; P less than 0.001). In turn, 1 h power output was related to each cyclists' VO2 at the blood lactate threshold (r = 0.93; P less than 0.001). Group 1 was not different from group 2 regarding VO2max (approximately 70 ml.kg-1.min-1 and 5.01 l.min-1) or lean body weight. However, group 1 bicycled 40 km on the road 10% faster than group 2 (P less than 0.05; 54 vs 60 min). Additionally, group 1 was able to generate 11% more power during the 1 h performance test than group 2 (P less than 0.05), and they averaged 90 +/- 1% VO2max compared with 86 +/- 2% VO2max in group 2 (P = 0.06). The higher performance power output of group 1 was produced primarily by generating higher peak torques about the center of the crank by applying larger vertical forces to the crank arm during the cycling downstroke. Compared with group 2, group 1 also produced higher peak torques and vertical forces during the downstroke even when cycling at the same absolute work rate as group 2. Factors possibly contributing to the ability of group 1 to produce higher "downstroke power" are a greater percentage of Type I muscle fibers (P less than 0.05) and a 23% greater (P less than 0.05) muscle capillary density compared with group 2. We have also observed a strong relationship between years of endurance training and percent Type I muscle fibers (r = 0.75; P less than 0.001). It appears that "elite-national class" cyclists have the ability to generate higher "downstroke power", possibly as a result of muscular adaptations stimulated by more years of endurance training.
在本研究中，我们评估了“国家级精英组”（即第1组；N = 9）和“优秀水平组”（即第2组；N = 6）自行车运动员的生理和生物力学反应。他们在实验室中，以最高功率输出在测力计上骑行1小时，模拟40公里计时赛。实际公路赛40公里计时赛成绩与1小时实验室性能测试期间的平均绝对功率高度相关（r = -0.88；P < 0.001）。反过来，1小时功率输出与每位自行车运动员在血乳酸阈值时的VO2相关（r = 0.93；P < 0.001）。在最大摄氧量（约70 ml·kg⁻¹·min⁻¹和5.01 l·min⁻¹）或瘦体重方面，第1组与第2组没有差异。然而，第1组在公路上骑行40公里的速度比第2组快10%（P < 0.05；54分钟对60分钟）。此外，在1小时性能测试期间，第1组比第2组能够多产生11%的功率（P < 0.05），并且他们的平均摄氧量为最大摄氧量的90±1%，而第2组为86±2%（P = 0.06）。第1组较高的性能功率输出主要是通过在骑行下行冲程中对曲柄臂施加更大的垂直力，从而围绕曲柄中心产生更高的峰值扭矩来实现的。与第2组相比，即使在与第2组相同的绝对工作速率下骑行时，第1组在下行冲程中也会产生更高的峰值扭矩和垂直力。可能有助于第1组产生更高“下行冲程功率”的因素是，与第2组相比，I型肌纤维的百分比更高（P < 0.05），肌肉毛细血管密度高23%（P < 0.05）。我们还观察到耐力训练年限与I型肌纤维百分比之间存在很强的关系（r = 0.75；P < 0.001）。看来“国家级精英组”自行车运动员有能力产生更高的“下行冲程功率”，这可能是多年耐力训练刺激肌肉适应的结果。
