Fritton S P, McLeod K J, Rubin C T
Center for Biomedical Engineering, CUNY Graduate School and Department of Mechanical Engineering, The City College of New York, NY 10031, USA.
J Biomech. 2000 Mar;33(3):317-25. doi: 10.1016/s0021-9290(99)00210-9.
We hypothesize that when a broad spectrum of bone strain is considered, strain history is similar for different bones in different species. Using a data collection protocol with a fine resolution, mid-diaphyseal strains were measured in vivo for both weightbearing and non-weightbearing bones in three species: dog, sheep, and turkey, with strain information collected continuously while the animals performed their natural daily activities. The daily strain history was quantified by both counting cyclic strain events (to quantify the distribution of strains of different magnitudes) and by estimating the average spectral characteristics of the strain (to quantify the frequency content of the strain signals). Counting of the daily (12-24 h) strain events show that large strains (> 1000 microstrain) occur relatively few times a day, while very small strains (< 10 microstrain) occur thousands of times a day. The lower magnitude strains (< approximately 200 microstrain) are found to be more uniform around the bone cross-section than the higher magnitude, peak strains. Strain dynamics are found to be well described by a power-law relationship and exhibit self-similar characteristics. These data lead to the suggestion that the organization of bone tissue is driven by the continual barrage of activity spanning a wide but consistent range of frequency and amplitude, and until the mechanism of bone's mechanosensory system is fully understood, all portions of bone's strain history should be considered to possibly play a role in bone adaptation.
我们推测，当考虑到广泛的骨应变范围时，不同物种的不同骨骼的应变历史是相似的。使用具有高分辨率的数据收集方案，在体内测量了狗、羊和火鸡这三种物种的承重骨和非承重骨的骨干中部应变，在动物进行其自然日常活动时持续收集应变信息。通过计算周期性应变事件（以量化不同大小应变的分布）和估计应变的平均频谱特征（以量化应变信号的频率成分）来量化每日应变历史。对每日（12 - 24小时）应变事件的计数表明，大应变（>1000微应变）每天出现的次数相对较少，而非常小的应变（<10微应变）每天出现数千次。发现较低大小的应变（<约200微应变）在骨横截面上比高大小的峰值应变更均匀。发现应变动态可以通过幂律关系很好地描述，并表现出自相似特征。这些数据表明，骨组织的组织是由跨越广泛但一致的频率和幅度范围的持续活动冲击驱动的，并且在骨的机械感觉系统的机制被完全理解之前，骨应变历史的所有部分都应被认为可能在骨适应中起作用。
