Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
Medical Device Research Institute, College of Science and Engineering Flinders University, Tonsley, SA, Australia.
J Bone Miner Res. 2018 Nov;33(11):1999-2006. doi: 10.1002/jbmr.3529. Epub 2018 Jul 18.
Advancing age and reduced loading are associated with a reduction in bone formation. Conversely, loading increases periosteal apposition and may reduce remodeling imbalance and slow age-related bone loss, an important outcome for the proximal femur, which is a common site of fracture. The ability to take advantage of bone's adaptive response to increase bone strength has been hampered by a lack of knowledge of which exercises and specific leg muscles load the superior femoral neck: a common region of microcrack initiation and progression following a sideways fall. We used an in vivo method of quantifying focal strains within the femoral neck in postmenopausal women during walking, stair ambulation, and jumping. Relative to walking, stair ambulation and jumping induced significantly higher strains in the anterior and superior aspects of the femoral neck, common regions of microcrack initiation and progression following a fall. The gluteus maximus, a hip extensor muscle, induced strains in the femoral neck during stair ambulation and jumping, in contrast to walking which induced strains via the iliopsoas, a hip flexor. The ground reaction force was closely associated with the level of strain during each task, providing a surrogate indicator of the potential for a given exercise to load the femoral neck. The gluteal muscles combined with an increased ground reaction force relative to walking induce high focal strains within the anterosuperior region of the femoral neck and therefore provide a target for exercise regimens designed to slow bone loss and maintain or improve microstructural strength. Model files used for calculating femoral neck strains are available at uitbl.mechse.illinois.edu/downloads © 2018 American Society for Bone and Mineral Research.
随着年龄的增长和负荷的减少，骨形成减少。相反，负荷增加骨膜的形成，可能减少重塑失衡和减缓与年龄相关的骨丢失，这是股骨近端的一个重要结果，股骨近端是骨折的常见部位。由于缺乏了解哪些运动和特定的腿部肌肉可以使股骨颈上部承受负荷，因此，利用骨骼对负荷的适应性反应来增加骨强度的能力受到了阻碍：这是在侧方跌倒后微裂纹起始和进展的常见部位。我们使用一种活体方法来测量绝经后女性行走、上下楼梯和跳跃时股骨颈内的局部应变。与行走相比，上下楼梯和跳跃会导致股骨颈前上方和上部的应变显著增加，这是跌倒后微裂纹起始和进展的常见部位。臀大肌是一种髋关节伸肌，在上下楼梯和跳跃时会在股骨颈中产生应变，而行走时则通过髂腰肌在股骨颈中产生应变。地面反作用力与每个任务中的应变水平密切相关，是给定运动对股骨颈负荷的潜在指标。与行走相比，臀肌和增加的地面反作用力会在股骨颈前上方区域产生高的局部应变，因此为旨在减缓骨质流失和维持或改善微观结构强度的运动方案提供了目标。用于计算股骨颈应变的模型文件可在 uitbl.mechse.illinois.edu/downloads 上获得 © 2018 美国骨骼与矿物质研究协会。
