MOE Key Laboratory of Dynamics and Control of Flight Vehicle, School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, China.
Air Force Medical Center, PLA, Beijing, 100142, China.
Biomech Model Mechanobiol. 2021 Aug;20(4):1599-1626. doi: 10.1007/s10237-021-01465-1. Epub 2021 May 29.
The role of intra-abdominal pressure (IAP) in spinal load reduction has remained controversial, partly because previous musculoskeletal models did not introduce the pressure generating mechanism. In this study, an integrated computational methodology is proposed to combine the IAP change with core muscle activations. An ideal gas relationship was introduced to calculate pressure distribution within the abdominal cavity. Additionally, based on flexible multibody dynamics, a muscle membrane element was developed by incorporating the muscular fiber deformation, inter-fiber stiffness, and volume constancy. This element was then utilized in discretizing the diaphragm and transversus abdominis, forming an IAP-muscle coupling system of the abdominal cavity. Based on this methodology, a forward dynamic simulation of spinal flexion was presented to examine the unloading effect of abdominal breathing. The results confirm that core muscle contraction during the abdominal breathing cycle can substantially reduce the forces of spinal compression together with trunk extensor muscles, and this effect is more pronounced when the IAP increase is produced by contraction of the transversus abdominis. This unloading effect still holds even with the co-activation of other abdominal muscles, providing a potential choice when designing trunk movements during weight-lifting tasks.
腹腔内压（IAP）在减轻脊柱负荷方面的作用一直存在争议，部分原因是先前的肌肉骨骼模型没有引入压力产生机制。在本研究中，提出了一种综合计算方法，将 IAP 变化与核心肌肉激活结合起来。引入理想气体关系来计算腹腔内的压力分布。此外，基于柔性多体动力学，通过结合肌肉纤维变形、纤维间刚度和体积恒定性，开发了一种肌肉膜元件。然后，该元件用于对横膈膜和腹横肌进行离散化，形成腹腔的 IAP-肌肉耦合系统。基于该方法，提出了脊柱前屈的正向动力学模拟，以检查腹式呼吸的卸荷效果。结果证实，腹式呼吸周期中核心肌肉的收缩可以显著降低脊柱压缩力，与躯干伸肌一起，当 IAP 通过腹横肌收缩增加时，这种效果更为明显。即使其他腹部肌肉共同激活，这种卸荷效果仍然存在，为举重任务中设计躯干运动提供了一种潜在选择。
