Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, Canada.
Department of Mechanical Engineering, College of Engineering, University of Saskatchewan, Canada.
J Biomech. 2019 Jun 11;90:149-152. doi: 10.1016/j.jbiomech.2019.04.042. Epub 2019 May 9.
The objective of this study was to validate a single-spring model in predicting measured impact forces during an outstretched arm falling scenario. Using an integrated force plate, impact forces were assessed from 10 young adults (5 males; 5 females), falling from planted knees onto outstretched arms, from a random order of drop heights: 3, 5, 7, 10, 15, 20, and 25 cm. A single-spring model incorporating body mass, drop height plus the estimated linear stiffness of the upper extremity (hand, wrist and arm) was used to predict impact force on the hand. We used an analysis of variance linearity test to test the validity of using a linear stiffness coefficient in the model. We used linear regression to assess variance (R) in experimental impact force predicted by the single-spring model. We derived optimum linear stiffness coefficients for male, female and sex-combined. Our results indicated that the association between experimental and predicted impact forces was linear (P < 0.05). Explain variance in experimental impact force was R = 0.82 for sex-combined, R = 0.88 for males and R = 0.84 for females. Optimum stiffness coefficients were 7436 N/m for sex-combined, 8989 N/m for males and 4527 N/m for females. In conclusion, a linear spring coefficient used in the single-spring model proved valid for predicting impact forces from fall heights up to 25 cm. Results also suggest the use of sex-specific spring coefficients when estimating impact force using the single-spring model. This model may improve impact force to bone strength ratios (factor-of-risk) and prediction of forearm and wrist fracture.
本研究旨在验证一种单弹簧模型，以预测伸展手臂下落场景中测量的冲击力量。使用集成力板，评估了 10 名年轻成年人（5 名男性；5 名女性）从种植的膝盖到伸展的手臂下落时的冲击力量，下落高度随机为：3、5、7、10、15、20 和 25cm。一个包含体重、下落高度加上上肢（手、腕和臂）估计线性刚度的单弹簧模型用于预测手上的冲击力量。我们使用方差线性测试分析来测试模型中使用线性刚度系数的有效性。我们使用线性回归来评估单弹簧模型预测的实验冲击力量的方差（R）。我们为男性、女性和男女混合得出了最佳线性刚度系数。我们的结果表明，实验和预测冲击力量之间的关联是线性的（P<0.05）。男女混合的 R=0.82，男性为 R=0.88，女性为 R=0.84，解释了实验冲击力量的方差。最佳刚度系数为男女混合 7436N/m，男性 8989N/m，女性 4527N/m。总之，单弹簧模型中使用的线性弹簧系数被证明可以有效预测高达 25cm 的下落高度的冲击力量。结果还表明，在使用单弹簧模型估计冲击力量时，使用性别特异性弹簧系数。该模型可能会提高冲击力量与骨强度比（风险因素）以及前臂和手腕骨折的预测。
