Takaishi T, Yasuda Y, Ono T, Moritani T
College of General Education, Nagoya City University, Japan.
Med Sci Sports Exerc. 1996 Dec;28(12):1492-7. doi: 10.1097/00005768-199612000-00008.
This study was designed to examine the optimal pedaling rate for pedaling exercise at a given work intensity for cyclists. Six college-aged cyclists each performed six sessions of heavy pedaling exercise at individually selected work rates based on their aerobic capacity. The optimal pedaling rate was evaluated on the basis of minimal neuromuscular fatigue as evidenced by the integrated electromyogram (iEMG) slope defined by the changes in iEMG as a function of time. The means of the iEMG slope demonstrated a quadratic curve versus pedaling rate. The mean values at 80 rpm (0.53 (SD 0.20) microV.min-1) and 90 rpm (0.67 (SD 0.23) microV.min-1) were significantly smaller than those values at any other pedaling rate. On the other hand, the mean value of oxygen uptake (VO2) expressed as a percent of the subject's maximal VO2 (% VO2max) at each pedaling rate also showed a quadratic curve with minimal values at about 60 or 70 rpm. VO2 at 70 rpm (84.0 (SD 5.0) % VO2max) was significantly smaller than those values at 80 rpm (86.3 (SD 3.5) % VO2max), 90 rpm (87.4 (SD 3.8) % VO2max), and 100 rpm (90.1 (SD 3.8) % VO2max). These data strongly suggest that the optimal pedaling rate estimated from neuromuscular fatigue in working muscles is not coincident with the pedaling rate at which the smallest VO2 was obtained, but with the preferred pedaling rate of the subjects. Our findings also suggest that the reason that cyclists prefer a higher pedaling rate is closely related to the development of neuromuscular fatigue in the working muscles.
本研究旨在确定在给定工作强度下，自行车骑行者蹬踏运动的最佳蹬踏频率。六名大学生年龄的自行车骑行者，根据各自的有氧能力，以个体选定的工作速率进行了六次高强度蹬踏运动。基于最小神经肌肉疲劳来评估最佳蹬踏频率，这由积分肌电图（iEMG）斜率来证明，该斜率由iEMG随时间变化定义。iEMG斜率的均值与蹬踏频率呈现二次曲线关系。80转/分钟（0.53（标准差0.20）微伏·分钟⁻¹）和90转/分钟（0.67（标准差0.23）微伏·分钟⁻¹）时的均值显著小于其他任何蹬踏频率时的值。另一方面，每个蹬踏频率下，以受试者最大摄氧量（VO₂）的百分比表示的摄氧量（VO₂）均值也呈现二次曲线，在约60或70转/分钟时最小值。70转/分钟时的VO₂（84.0（标准差5.0）%VO₂max）显著小于80转/分钟（86.3（标准差3.5）%VO₂max）、90转/分钟（87.4（标准差3.8）%VO₂max）和100转/分钟（90.1（标准差3.8）%VO₂max）时的值。这些数据有力地表明，从工作肌肉的神经肌肉疲劳估计出的最佳蹬踏频率，与获得最小VO₂的蹬踏频率不一致，而是与受试者偏好的蹬踏频率一致。我们的研究结果还表明，自行车骑行者偏好较高蹬踏频率的原因与工作肌肉中神经肌肉疲劳的发展密切相关。
