Actis Jason A, Honegger Jasmin D, Gates Deanna H, Petrella Anthony J, Nolasco Luis A, Silverman Anne K
Department of Mechanical Engineering, Colorado School of Mines, Golden, CO 80401, USA.
School of Kinesiology, University of Michigan, Ann Arbor, MI 48109, USA.
J Biomech. 2018 Feb 8;68:107-114. doi: 10.1016/j.jbiomech.2017.12.001. Epub 2017 Dec 13.
Low back mechanics are important to quantify to study injury, pain and disability. As in vivo forces are difficult to measure directly, modeling approaches are commonly used to estimate these forces. Validation of model estimates is critical to gain confidence in modeling results across populations of interest, such as people with lower-limb amputation. Motion capture, ground reaction force and electromyographic data were collected from ten participants without an amputation (five male/five female) and five participants with a unilateral transtibial amputation (four male/one female) during trunk-pelvis range of motion trials in flexion/extension, lateral bending and axial rotation. A musculoskeletal model with a detailed lumbar spine and the legs including 294 muscles was used to predict L4-L5 loading and muscle activations using static optimization. Model estimates of L4-L5 intervertebral joint loading were compared to measured intradiscal pressures from the literature and muscle activations were compared to electromyographic signals. Model loading estimates were only significantly different from experimental measurements during trunk extension for males without an amputation and for people with an amputation, which may suggest a greater portion of L4-L5 axial load transfer through the facet joints, as facet loads are not captured by intradiscal pressure transducers. Pressure estimates between the model and previous work were not significantly different for flexion, lateral bending or axial rotation. Timing of model-estimated muscle activations compared well with electromyographic activity of the lumbar paraspinals and upper erector spinae. Validated estimates of low back loading can increase the applicability of musculoskeletal models to clinical diagnosis and treatment.
量化下背部力学对于研究损伤、疼痛和残疾情况很重要。由于体内力难以直接测量，通常使用建模方法来估计这些力。模型估计的验证对于在感兴趣的人群（如下肢截肢者）中获得对建模结果的信心至关重要。在躯干 - 骨盆屈伸、侧屈和轴向旋转的运动范围内进行试验时，从十名未截肢参与者（五名男性/五名女性）和五名单侧经胫骨截肢参与者（四名男性/一名女性）收集了运动捕捉、地面反作用力和肌电图数据。使用具有详细腰椎和腿部（包括294块肌肉）的肌肉骨骼模型，通过静态优化来预测L4 - L5负荷和肌肉激活情况。将L4 - L5椎间关节负荷的模型估计值与文献中测量的椎间盘内压力进行比较，并将肌肉激活情况与肌电图信号进行比较。模型负荷估计值仅在未截肢男性和截肢者的躯干伸展过程中与实验测量值有显著差异，这可能表明L4 - L5轴向负荷通过小关节传递的比例更大，因为椎间盘内压力传感器无法捕捉小关节负荷。在屈伸、侧屈或轴向旋转时，模型与先前研究的压力估计值没有显著差异。模型估计的肌肉激活时间与腰背部脊柱旁肌和上竖脊肌的肌电图活动比较吻合。经过验证的下背部负荷估计可以提高肌肉骨骼模型在临床诊断和治疗中的适用性。
