Yen S T, Andrew P D, Cummings G S
Department of Physical Therapy, College of Health Sciences, Georgia State University, USA.
Hiroshima J Med Sci. 1998 Dec;47(4):139-43.
In this study we assessed the short-term effect of correcting leg length discrepancy on a vigorously performed task of resisted full body extension in 10 men, 18 to 35 years old, who had estimated leg length discrepancies of 10-15 mm. Using a cable ergometer we examined work performed, initial peak tension exerted on the ergometer, second peak tension, time to first peak tension, and mean velocity of the whole task. Each subject performed the task both with and without a heel lift, introduced to equalize leg length. The interval between testing under these two conditions was 48 hr. In the task of pulling the cable upward, each subject began from floor level with knees and trunk flexed, progressing to full body extension with the arms pulling the cable overhead with maximal effort. For each trial the task was repeated 15 times, with intervals of 90 seconds between the repetitions. Use of the lift failed to have a statistically significant effect on any of the variables, although it clearly enabled three of the subjects to exert greater strength with the arms and trunk during the second peak tension. This suggests that 1) overall body extension is influenced by too many factors to be affected in a consistently predictable way by a heel lift to correct leg length discrepancy, and 2) the heel lift may aid certain subjects with leg length discrepancy specifically during extension of the trunk in this task.
在本研究中，我们评估了矫正腿长差异对10名年龄在18至35岁之间、估计腿长差异为10 - 15毫米的男性进行的全身抗阻伸展剧烈任务的短期影响。我们使用缆索测力计检测了所完成的功、测力计上施加的初始峰值张力、第二峰值张力、达到第一峰值张力的时间以及整个任务的平均速度。每个受试者在有和没有用于均衡腿长的足跟垫的两种情况下都执行该任务。这两种条件下测试的间隔时间为48小时。在向上拉缆索的任务中，每个受试者从地面开始，膝盖和躯干弯曲，然后通过手臂最大程度地向上拉缆索使全身伸展。每次试验该任务重复15次，重复之间间隔90秒。尽管足跟垫明显使三名受试者在第二峰值张力期间能够用手臂和躯干施加更大的力量，但使用足跟垫对任何变量均未产生统计学上的显著影响。这表明：1）全身伸展受太多因素影响，以至于通过足跟垫矫正腿长差异并不能以一致可预测的方式产生影响；2）在这项任务中，足跟垫可能特别有助于某些有腿长差异的受试者在躯干伸展期间发力。
