Cycling technique is steeped in cultural lore. One deeply held belief is that "pulling-up" to lift the leg (increased muscular leg flexion) will optimize technique and improve efficiency. In contrast, scientific evidence suggests that when cyclists are instructed to pull-up efficiency decreases. However, such interventions may not have allowed sufficient time for cyclists to adapt and refine their technique. This case study documented how a cyclist with a complete unilateral limb amputation consumed metabolic power to produce mechanical power during single-leg cycling. The cyclist was a 4-time U.S. National Paralympic Champion who performed single-leg cycling for 7yrs and thus was fully adapted to pull-up. We hypothesized that a counterweight system, which reduced the requirement to pull-up, would decrease metabolic power and increase efficiency for this cyclist. The cyclist performed submaximal cycling (100, 135, 170, 205W, 80rpm, 5min) with and without a counterweight (10kg) on the unused crank. Expired gasses were measured, and metabolic power and gross efficiency were calculated. Metabolic power decreased on average by 87±7W (p<0.001) and gross efficiency increased from 16.3±1.9 to 18.0±1.8% (p<0.001) when cycling with the counterweight. During counterweighted single-leg cycling, the metabolic power of unloaded cycling decreased (317 vs. 238W) and delta efficiency was similar (25.2 vs. 25.5%). Results demonstrated that significant metabolic power was associated with pulling-up to produce muscular leg flexion power even in a cyclist who pulled-up substantially during cycling. Our findings confirm observations from previous studies that altered pedaling technique acutely and indicate that pulling-up during cycling is less efficient.

中文翻译：

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被截肢者骑自行车者的代谢能力和效率：对自行车技术的启示

自行车技术深深地浸入了文化遗产。一种深信不疑的信念是，“抬起腿”来抬起腿（增加腿部肌肉的弯曲度）将优化技术并提高效率。相反，科学证据表明，当骑自行车的人被指示上拉效率降低时。但是，这样的干预可能没有为骑自行车的人留出足够的时间来适应和完善他们的技术。该案例研究记录了单肢完全截肢的骑车人如何在单腿骑行过程中消耗代谢力以产生机械能。这位骑自行车的人是4次美国国家残奥会冠军，他单腿骑自行车进行了7年，因此完全适合上拉。我们假设有一个配重系统，该系统减少了上拉的要求，会降低该自行车手的代谢能力并提高其效率。骑自行车的人在未使用的曲柄上有和没有配重（10kg）的情况下进行了次最大循环（100、135、170、205W，80rpm，5分钟）。测量了过期的气体，并计算了代谢能力和总效率。当与配重一起骑行时，代谢功率平均降低87±7W（p <0.001），总效率从16.3±1.9提高到18.0±1.8％（p <0.001）。在配重单腿自行车运动中，空载自行车的代谢能力下降（317 vs. 238W），Δ效率相似（25.2 vs. 25.5％）。结果表明，即使在骑自行车的人在自行车运动期间显着上拉的情况下，显着的代谢能力也与上拉产生肌肉的腿屈曲能力有关。