腰骶脊柱在向后摔倒时的力传递。
Transmission of force in the lumbosacral spine during backward falls.
机构信息
Orthopaedic and Injury Biomechanics Group, Department of Mechanical Engineering, University of British Columbia, Vancouver, British Columbia, Canada.
出版信息
Spine (Phila Pa 1976). 2012 Apr 20;37(9):E519-27. doi: 10.1097/BRS.0b013e31823ecae0.
STUDY DESIGN
Mathematical model, combined with and verified using human subject data.
OBJECTIVE
(1) To develop and verify a lumped-parameter mathematical model for prediction of spine forces during backward falls; (2) to use this model to evaluate the effect of floor stiffness on spine forces during falls; and (3) to compare predicted impact forces with forces previously measured to fracture the spine.
SUMMARY OF BACKGROUND DATA
Vertebral fractures are the most common osteoporotic fractures and commonly result from falls from standing height. Compliant flooring reduces the force at the ground during a backward fall from standing; however, the effect on spine forces is unknown.
METHODS
A 6-df model of the body was developed and verified using data from 10 human subjects falling from standing onto 3 types of compliant floors (soft: 59 kN/m, medium: 67 kN/m, and firm: 95 kN/m). The simulated ground forces were compared with those measured experimentally. The model was also used to assess the effect of floor stiffness on spine forces at various intervertebral levels.
RESULTS
There was less than 14% difference between model predictions and experimentally measured peak ground reaction forces, when averaged over all floor conditions. When compared with the rigid floor, average peak spine force attenuations of 46%, 43%, and 41% were achieved with the soft, medium, and firm floors, respectively (3.7, 3.9, 4.1 kN vs. 6.9 kN at L4/L5). Spine forces were lower than those at the ground and decreased cranially (4.9, 3.9, 3.7, 3.5 kN at the ground, L5/S1, L4/L5, and L3/L4, respectively, for the soft floor).
CONCLUSION
Lowering the floor stiffness (from 400 to 59 kN/m) can attenuate peak lumbosacral spine forces in a backward fall onto the buttocks from standing by 46% (average peak from 6.9 to 3.7 kN at L4/L5) to values closer to the average tolerance of the spine to fracture (3.4 kN).
研究设计
数学模型，结合并验证人体受试者数据。
目的
（1）开发并验证用于预测背部跌倒时脊柱力的集总参数数学模型；（2）使用该模型评估跌倒时地板刚度对脊柱力的影响；（3）将预测的撞击力与以前测量到的导致脊柱骨折的力进行比较。
背景资料总结
椎体骨折是最常见的骨质疏松性骨折，通常由站立高度跌倒引起。顺应性地板可减少站立时向后跌倒时地面的力；然而，对脊柱力的影响尚不清楚。
方法
建立了一个 6 自由度的人体模型，并使用来自 10 名从站立状态跌倒在 3 种顺应性地板（软：59 kN/m，中：67 kN/m，硬：95 kN/m）上的人体受试者的数据进行验证。模拟地面力与实验测量值进行比较。该模型还用于评估地板刚度对不同椎间水平脊柱力的影响。
结果
在所有地板条件下，模型预测值与实验测量的峰值地面反作用力的差异小于 14%。与刚性地板相比，软、中、硬地板分别使平均峰值脊柱力衰减 46%、43%和 41%（4.1 kN 比 L4/L5 处的 6.9 kN）。脊柱力低于地面力，并向头侧降低（软地板处地面为 4.9 kN，L5/S1、L4/L5 和 L3/L4 处分别为 3.9 kN、3.7 kN、3.5 kN）。
结论
降低地板刚度（从 400 kN/m 降低至 59 kN/m）可使站立状态向后跌倒臀部时的腰骶脊柱力衰减 46%（L4/L5 处平均峰值从 6.9 kN 降至 3.7 kN），使其更接近脊柱骨折平均耐受值（3.4 kN）。
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