Foods and Nutrition, Purdue University, West Lafayette, IN, USA; Health and Human Performance, Dalhousie University, Halifax, NS, Canada.
J Biomech. 2009 Dec 11;42(16):2734-8. doi: 10.1016/j.jbiomech.2009.08.002. Epub 2009 Sep 25.
Animal models are commonly used to test the efficacy of impact loading regimens on bone strength. We designed an inexpensive force platform to concurrently measure the separate peak vertical impact forces produced by the fore and hindfeet of immature F-344 rats when dropped onto the platform. The force platform consisted of three load cells placed in a triangular pattern under a flat plate. Rats were dropped from heights of 30, 45 and 60 cm onto the platform so that they landed on all four feet concurrently. The peak vertical impact forces produced by the feet of the rats were measured using a sampling frequency of 100 kHz. The location of each foot at landing relative to the load cells, and the force received by each load cell were combined in a series of static equations to solve for the vertical impact forces produced by the fore and hindfeet. The forces produced by feet when rats stood on the single platform were similarly determined. The forces exerted separately by the fore and hindfeet of young rats when landing on the plate as a ratio to standing forces were then calculated. Rats when standing bore more weight on their hindfeet but landed with more weight on their forefeet, which provides rationale for the greater response to landing forces of bones in the forelimbs than those in the hindlimbs. This system provided a useful method to simultaneously measure peak vertical impact forces in fore and hindfeet in rats.
动物模型常用于测试冲击负荷方案对骨强度的疗效。我们设计了一种廉价的力平台，可同时测量在平台上掉落的未成熟 F-344 大鼠前足和后足产生的单独的垂直冲击峰值力。力平台由三个放置在平板下的三角形模式的负载单元组成。大鼠从 30、45 和 60 厘米的高度掉落平台，使它们的四个脚同时着地。使用 100 kHz 的采样频率测量大鼠脚部产生的垂直冲击峰值力。每个脚在着陆时相对于负载单元的位置以及每个负载单元接收到的力结合在一系列静态方程中，以求解前足和后足产生的垂直冲击力。当大鼠站在单个平台上时，同样确定了脚产生的力。然后计算了大鼠站在平台上时前脚和后脚单独产生的力与站立时的力的比值。当大鼠站立时，后脚承受的重量更大，但前脚着地时的重量更大，这为前肢骨骼对落地力的反应大于后肢骨骼提供了合理的依据。该系统提供了一种有用的方法，可同时测量大鼠前足和后足的垂直冲击峰值力。
