Whalen R, Quintana J, Emery J
NASA/Ames Research Center, Moffett Field, CA 94035.
Physiologist. 1993;36(1 Suppl):S139-40.
Theoretical models and experimental studies of bone remodeling have identified peak cyclic force levels (or cyclic tissue strain energy density), number of daily loading cycles, and load (strain) rate as possible contributors to the bone modeling and remodeling stimulus. To test our theoretical model and further investigate the influence of mechanical forces on bone density, we have focused on the calcaneus as a model site loaded by calcaneal surface tractions which are predominantly determined by the magnitude of the external ground reaction force (GRF). During daily activity the body is subjected to a random external loading history supplied primarily by the GRF consisting of body weight (BW) plus inertial forces (related to intensity of activity) accelerating the body center of mass. We have hypothesized that monitoring the vertical component of the GRF (GRFz) may provide a useful method of quantifying activity level in order to investigate the influence of mechanical forces on muscle and bone. GRF loading histories among individuals are known to vary greatly in peak force levels and daily cycles and we suggest these differences may be reflected in differences in lower limb musculoskeletal properties. We report here development of instrumentation to monitor the vertical component of the ground reaction force during normal daily activity.
骨重塑的理论模型和实验研究已经确定，峰值循环力水平（或循环组织应变能密度）、每日加载循环次数以及加载（应变）速率可能是骨建模和重塑刺激的影响因素。为了验证我们的理论模型并进一步研究机械力对骨密度的影响，我们将跟骨作为一个模型部位进行研究，该部位受到跟骨表面牵引力的作用，而跟骨表面牵引力主要由外部地面反作用力（GRF）的大小决定。在日常活动中，身体受到主要由GRF提供的随机外部加载历史，GRF由体重（BW）加上使身体质心加速的惯性力（与活动强度有关）组成。我们假设监测GRF的垂直分量（GRFz）可能提供一种量化活动水平的有用方法，以便研究机械力对肌肉和骨骼的影响。已知个体之间的GRF加载历史在峰值力水平和每日循环方面差异很大，我们认为这些差异可能反映在下肢肌肉骨骼特性的差异中。我们在此报告用于监测正常日常活动期间地面反作用力垂直分量的仪器的开发情况。
