Peter Harrison Centre for Disability Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UNITED KINGDOM.
School of Health Sciences, University of Southampton, UNITED KINGDOM.
Med Sci Sports Exerc. 2019 Nov;51(11):2265-2273. doi: 10.1249/MSS.0000000000002062.
To determine the effects of horizontal crank position on economy and upper limb kinematics in recumbent handcycling.
Fifteen trained handcyclists performed trials at 50% and 70% of their peak aerobic power output (POPeak), determined during a maximal exercise test, in each horizontal crank position. Four horizontal crank positions, 94%, 97%, 100%, and 103% of arm length, were investigated. Horizontal crank positions were defined as the distance between the acromion angle to the center of the handgrip, while the crank arm was parallel to the floor and pointing away from the participant. Economy and upper limb kinematics were calculated during the final minute of each 3-min trial.
Horizontal crank position significantly affected handcycling economy at 70% POPeak (P < 0.01) but not at 50% POPeak (P = 0.44). The 97% horizontal crank position (16.0 [1.5] mL·min·W) was significantly more economical than the 94% (16.7 (1.9) mL·min·W) (P = 0.04) and 103% (16.6 (1.7) mL·min·W) (P < 0.01) positions. The 100% horizontal crank position (16.2 (1.7) mL·min·W) was significantly more economical than the 103% position (P < 0.01). Statistical parametric mapping indicated that an increase in horizontal crank position, from 94% to 103%, caused a significant increase in elbow extension, shoulder flexion, adduction, internal rotation, scapular internal rotation, wrist flexion, clavicle depression and clavicle protraction between 0% and 50% (0°-180°) of the cycle (P < 0.05).
Positioning the cranks at 97% to 100% of the athletes' arm length improved handcycling economy at 70% POPeak as, potentially, the musculature surrounding the joints of the upper limb were in a more favorable position to produce force economically.
确定水平曲柄位置对卧姿手摇车经济性和上肢运动学的影响。
15 名经过训练的手摇车手在最大运动试验中确定的 50%和 70%的峰值有氧能力输出（POPeak）下，在每个水平曲柄位置进行试验。研究了 4 种水平曲柄位置，即手臂长度的 94%、97%、100%和 103%。水平曲柄位置定义为三角肌角到手柄中心之间的距离，而曲柄臂与地面平行并指向远离参与者。在每次 3 分钟试验的最后 1 分钟计算经济性和上肢运动学。
水平曲柄位置显著影响 70%POPeak 时的手摇车经济性（P<0.01），但对 50%POPeak 时的经济性无影响（P=0.44）。97%的水平曲柄位置（16.0[1.5]mL·min·W）比 94%（16.7[1.9]mL·min·W）（P=0.04）和 103%（16.6[1.7]mL·min·W）（P<0.01）位置更经济。100%的水平曲柄位置（16.2[1.7]mL·min·W）比 103%位置更经济（P<0.01）。统计参数映射表明，从 94%增加到 103%的水平曲柄位置导致肘部伸展、肩部弯曲、内收、内旋、肩胛骨内旋、腕关节弯曲、锁骨下降和锁骨前伸在 0%到 50%（0°-180°）的周期内显著增加（P<0.05）。
将曲柄定位在运动员手臂长度的 97%到 100%，可以提高 70%POPeak 时的手摇车经济性，因为上肢关节周围的肌肉可能处于更有利于经济地产生力的位置。
