van der Woude L H, van Kranen E, Ariëns G, Rozendal R H, Veeger H E
Faculty of Human Movement Sciences, Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
J Med Eng Technol. 1995 Jul-Aug;19(4):123-31. doi: 10.3109/03091909509012418.
The physical strain and mechanical efficiency of manual wheelchair propulsion using handrim and hubcrank propelled racing wheelchairs were studied during a submaximal wheelchair exercise test on a stationary roller ergometer. Ten healthy male able-bodied subjects conducted two exercise tests in a random order and measurements of phyical strain (oxygen uptake, minute ventilation, respiratory exchange ratio, heart rate) and gross mechanical efficiency were obtained. During the experiment torque data, speed and power output were determined at a sample frequency of 0.1 Hz. Analysis of variance for repeated measures (p < 0.05) was used to establish differences. The hubcrank propulsion mechanism showed a significantly lower physical strain and higher gross mechanical efficiency in comparison with the handrim propulsion mechanism. The lower strain and higher efficiency in propelling the hubcrank partly seems to be due to the continuous biphasic cyclic propulsion movement, which allows both push and pull forces to be exerted. This involves flexor and extensor muscles around elbow and shoulder, leading to a reduced tendency to fatigue in individual muscles in the upper extremity. The more natural and neutral wrist-hand orientation also seems to diminish finger flexor activity and wrist-stabilizing muscle activity, and will thus reduce physical strain both with respect to the cardiorespiratory and musculoskeletal systems. The latter may influence the tendency to develop carpal tunnel problems positively. The reduced strain of the hubcrank propulsion mechanism clearly has a number of advantages over handrims for the human engine in the short and long run. However, technical innovation should address current practical problems of steering and braking. Clearly, hubcranks can be used in low-seated wheelchairs (i.e. racing wheelchairs) only, and in subjects with a sufficiently large range of motion in the upper extremity. Moreover, the increased width is a drawback of hubcranks. Care should be taken while negotiating door posts.
在固定滚筒测力计上进行的次最大运动轮椅测试期间，研究了使用手轮圈和轮毂曲柄驱动的竞赛轮椅进行手动轮椅推进时的身体应变和机械效率。十名健康的男性健全受试者以随机顺序进行了两次运动测试，并获得了身体应变（摄氧量、分钟通气量、呼吸交换率、心率）和总机械效率的测量值。在实验过程中，以0.1Hz的采样频率确定扭矩数据、速度和功率输出。使用重复测量方差分析（p<0.05）来确定差异。与手轮圈推进机制相比，轮毂曲柄推进机制显示出明显更低的身体应变和更高的总机械效率。轮毂曲柄推进时较低的应变和较高的效率部分似乎是由于连续的双相循环推进运动，这种运动允许施加推和拉力。这涉及到肘部和肩部周围的屈肌和伸肌，导致上肢单个肌肉疲劳的趋势降低。更自然和中立的手腕-手部姿势似乎也会减少手指屈肌活动和手腕稳定肌肉活动，从而减少心肺和肌肉骨骼系统方面的身体应变。后者可能对腕管问题的发生趋势产生积极影响。从短期和长期来看，轮毂曲柄推进机制降低的应变显然比手轮圈对人体发动机有许多优势。然而，技术创新应解决当前转向和制动的实际问题。显然，轮毂曲柄仅可用于低座轮椅（即竞赛轮椅），且适用于上肢有足够大范围运动的受试者。此外，宽度增加是轮毂曲柄的一个缺点。在通过门柱时应小心。
