Burr D B, Milgrom C, Fyhrie D, Forwood M, Nyska M, Finestone A, Hoshaw S, Saiag E, Simkin A
Department of Anatomy, Indiana University School of Medicine, Indianapolis 46227, USA.
Bone. 1996 May;18(5):405-10. doi: 10.1016/8756-3282(96)00028-2.
Our understanding of mechanical controls on bone remodeling comes from studies of animals with surgically implanted strain gages, but in vivo strain measurements have been made in a single human only once. That study showed that strains in the human tibia during walking and running are well below the fracture threshold. However, strains have never been monitored in vivo during vigorous activity in people, even though prolonged strenuous activity may be responsible for the occurrence of stress fractures. We hypothesized that strains > 3000 microstrain could be produced on the human tibial midshaft during vigorous activity. Strains were measured on the tibiae of two subjects via implanted strain gauges under conditions similar to those experienced by Israeli infantry recruits. Principal compressive and shear strains were greatest for uphill and downhill zigzag running, reaching nearly 2000 microstrain in some cases, about three times higher than recorded during walking. Strain rates were highest during sprinting and downhill running, reaching 0.050/sec. These results show that strain is maintained below 2000 microstrain even under conditions of strenuous activity. Strain rates are higher than previously recorded in human studies, but well within the range reported for running animals.
我们对骨骼重塑机械控制的理解来自于对植入应变计的动物的研究，但体内应变测量仅在一个人身上进行过一次。该研究表明，行走和跑步时人类胫骨的应变远低于骨折阈值。然而，即使长时间剧烈活动可能是应力性骨折发生的原因，但人们在剧烈活动期间从未进行过体内应变监测。我们假设，在剧烈活动期间，人类胫骨中轴上可能会产生大于3000微应变的应变。在与以色列步兵新兵所经历的条件相似的情况下，通过植入应变计测量了两名受试者胫骨上的应变。上坡和下坡之字形跑步时的主压缩应变和剪切应变最大，在某些情况下达到近2000微应变，约为行走时记录值的三倍。冲刺和下坡跑步时应变率最高，达到0.050/秒。这些结果表明，即使在剧烈活动条件下，应变也能保持在2000微应变以下。应变率高于之前人类研究中记录的值，但仍在报道的奔跑动物的范围内。
