Pearson Simon N, Hume Patria A, Cronin John, Slyfield David
Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Faculty of Health and Environmental Science, Auckland University of Technology, Private Bag 92006, Auckland 1020, New Zealand.
Queensland Academy of Sport, QLD Sport & Athletics Centre, Kessels Rd, Nathan QLD 4111, Australia.
Sports (Basel). 2016 Jun 27;4(3):37. doi: 10.3390/sports4030037.
Grinding is a key physical element in America's Cup sailing. This study aimed to describe kinematics and muscle activation patterns in relation to torque applied in forward and backward grinding. Ten male America's Cup sailors (33.6 ± 5.7 years, 97.9 ± 13.4 kg, 186.6 ± 7.4 cm) completed forward and backward grinding on a customised grinding ergometer. In forward grinding peak torque (77 Nm) occurred at 95° (0° = crank vertically up) on the downward section of the rotation at the end of shoulder flexion and elbow extension. Backward grinding torque peaked at 35° (69 Nm) following the pull action (shoulder extension, elbow flexion) across the top of the rotation. During forward grinding, relatively high levels of torque (>50 Nm) were maintained through the majority (72%) of the cycle, compared to 47% for backward grinding, with sections of low torque corresponding with low numbers of active muscles. Variation in torque was negatively associated with forward grinding performance ( = -0.60; 90% CI -0.88 to -0.02), but positively associated with backward performance ( = 0.48; CI = -0.15 to 0.83). Magnitude and distribution of torque generation differed according to grinding direction and presents an argument for divergent training methods to improve forward and backward grinding performance.
绞磨是美洲杯帆船赛中的一个关键物理要素。本研究旨在描述与向前和向后绞磨时施加的扭矩相关的运动学和肌肉激活模式。十名男性美洲杯帆船赛船员（年龄33.6±5.7岁，体重97.9±13.4千克，身高186.6±7.4厘米）在定制的绞磨测力计上完成了向前和向后绞磨。在向前绞磨时，峰值扭矩（77牛米）出现在肩部屈曲和肘部伸展结束时旋转向下部分的95°（0°=曲柄垂直向上）处。向后绞磨扭矩在越过旋转顶部的拉动作（肩部伸展、肘部屈曲）后，于35°（69牛米）达到峰值。在向前绞磨过程中，在大部分（72%）周期内保持了相对较高水平的扭矩（>50牛米），相比之下，向后绞磨为47%，低扭矩部分与活跃肌肉数量少相对应。扭矩变化与向前绞磨性能呈负相关（=-0.60；90%置信区间-0.88至-0.02），但与向后性能呈正相关（=0.48；置信区间=-0.15至0.83）。根据绞磨方向，扭矩产生的大小和分布有所不同，这为采用不同的训练方法来提高向前和向后绞磨性能提供了依据。
