Laboratoire de Neurosciences Fonctionnelles et Pathologies, Université Lille 2, CNRS, Lille, France.
Laboratoire de Neurosciences Fonctionnelles et Pathologies, Université Lille 2, CNRS, Lille, France.
J Biomech. 2014 May 7;47(7):1603-8. doi: 10.1016/j.jbiomech.2014.03.005. Epub 2014 Mar 12.
The study investigated the mediolateral control of upright stance in 16 healthy, young adults. The model analyzed the body weight distribution and center of pressure location mechanisms under three stance width conditions (feet close, under standard condition, and apart). Our first objective was to discuss some methodological requirements to investigate the contribution of both mechanisms by means of two platforms. It is proposed that both the amplitude contribution (in variability analyses) and active contribution (in cross-correlation analyses) need to be studied distinctively. These analyses may be concerned with the strength and the degree of active contributions, respectively. Based on this theoretical proposition, we expected and found that the amplitude contribution of both mechanisms was higher and lower in wide and narrow stances compared with that in the standard stance, respectively. Indeed, the closer the two reaction forces, the lower their mechanical contribution. As expected, the active contribution of both mechanisms was significantly lower and higher in wide and narrow stances, respectively. Indeed, the further the feet apart, the less active both mechanisms needed to be to control mediolateral stance. Overall, only the center of pressure location mechanism really changed its significant contribution to control mediolateral stance under the three conditions. The result is important because this mechanism is known to be secondary, weaker than the body weight distribution mechanism to control mediolateral stance. In practical terms, these findings may explain why the mediolateral variability of center of pressure displacement was significantly higher in narrow stance but not lower in wide stance.
本研究调查了 16 名健康年轻成年人在直立姿势下的横向控制。该模型分析了在三种站位宽度条件下（双脚靠近、标准条件和分开）的体重分布和中心压力位置机制。我们的第一个目标是讨论一些方法学要求，以便通过两个平台研究两种机制的贡献。建议分别研究两种机制的幅度贡献（在变异性分析中）和主动贡献（在互相关分析中）。这些分析可能分别涉及强度和主动贡献的程度。基于这一理论假设，我们预期并发现，与标准站位相比，两种机制的幅度贡献在宽站位和窄站位时分别更高和更低。实际上，两个反作用力越接近，其机械贡献越低。正如预期的那样，两种机制的主动贡献在宽站位和窄站位时分别更低和更高。实际上，双脚分开得越远，两种机制就越不需要主动参与来控制横向平衡。总的来说，只有中心压力位置机制真正改变了它在三种条件下对控制横向平衡的显著贡献。该结果很重要，因为该机制已知是次要的，在控制横向平衡方面比体重分布机制弱。实际上，这些发现可以解释为什么在窄站位时中心压力位移的横向变异性显著更高，但在宽站位时却没有更低。
