Effect of the "squat protective response" on impact velocity during backward falls
Effect of the "squat protective response" on impact velocity during backward falls
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DOI：
10.1016/j.jbiomech.2003.12.015
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发表时间：
2004-09-01
影响因子：
2.4
通讯作者：
Maurer, J
中科院分区：
文献类型：
--
作者：
Robinovitch, SN;Brumer, R;Maurer, J
在坠落中受伤的风险取决于身体各部分在撞击时的位置和速度。降低冲击速度的一种技术是在下降过程中吸收下肢肌肉的能量，就像蹲或坐的时候一样。然而，这种反应的保护价值可能取决于反应开始时的下降时间。我们通过对年轻女性（n=23，年龄21-29岁）进行向后跌倒实验来验证这一假设，这些女性在突然从倾斜位置释放后摔倒在柔软的健身房床垫上。在试验中，受试者从5度的倾斜中解脱出来，当使用深蹲时，平均撞击速度比禁止时降低了18%。此外，释放角的增加导致2度和5度倾角之间的平均冲击速度增加8%，5度和12度倾角之间的平均冲击速度增加7%。这是由于峰值伸肌扭矩和峰值屈曲旋转的下降，以及相应的关节功和碰撞势能的减少。这些结果表明，在下降过程中深蹲可以降低冲击的严重程度，但反应的有效性取决于开始时的下降阶段，随着下降的进展和不平衡状态的日益严重，效果会逐渐减少。(C) 2004 Elsevier Ltd.版权所有。
Risk for injury during a fall depends on the position and velocity of the body segments at the moment of impact. One technique for reducing impact velocity is to absorb energy in the lower extremity muscles during descent, as occurs during squatting or sitting. However, the protective value of this response may depend on the time during descent when the response is initiated. We tested this hypothesis by conducting backward falling experiments with young women (n=23; aged 21-29 years), who fell onto a soft gymnasium mattress after being suddenly releasing from an inclined position. In trials where subjects were released from a 5degrees lean, average impact velocities were reduced by 18% when squatting was utilized as opposed to inhibited. Furthermore, increases in the release angle caused an increase in average impact velocity of 8% between lean angles of 2degrees and 5degrees, and 7% between lean angles of 5degrees and 12degrees. This was due to declines in peak extensor torques and peak flexion rotations, and corresponding reductions in both joint work and potential energy at impact. These results suggest that squatting during descent reduces impact severity, but the effectiveness of the response depends on the stage during descent when it is initiated, diminishing in benefit as the fall progresses and the state of imbalance grows increasingly severe. (C) 2004 Elsevier Ltd. All rights reserved.