Faculty of Rehabilitation Medicine, Department of Physical Therapy, University of Alberta, Corbett Hall, 8205, 114 Street NW, Edmonton, Alberta, T6G 2G4, Canada.
Musculoskelet Sci Pract. 2021 Apr;52:102301. doi: 10.1016/j.msksp.2020.102301. Epub 2020 Nov 16.
Device-based measurement of lumbar spinal stiffness has the potential to identify patients with low back pain who are more likely to improve with spinal manipulative therapy. This study evaluates how voluntary contraction of spine muscles may impact stiffness measures.
To determine how the contraction of different spinal muscles may influence spinal stiffness at all lumbar levels.
Experimental study.
A mechanical device was used to measure spinal stiffness (N/mm) from L1 to L5 in 12 asymptomatic participants, while muscle activity from four pairs of thoracolumbar muscles was recorded. A baseline measurement was collected with the participants holding their breath at normal exhalation. Participants stiffness was then measured while performing (1) an isometric hip extension, (2) an isometric shoulder flexion, and (3) a deep held inhalation. Mixed-model ANOVAs were used to evaluate the effects of the perturbations on spinal stiffness at each lumbar level. Friedman's test was then computed to evaluate the differences in muscle activity between the perturbations.
Globally, the designed perturbations generated activity in different muscles with different magnitudes (P-values≤0.05). Increased spinal stiffness was observed at each spinal level during the hip extension, and at L5 during the held inhalation (P-values<0.05). A differential effect of the spinal levels on the spinal stiffness was observed during the hip extension and held inhalation (P-values<0.05).
This study provides evidence that the magnitude of muscle activity influences spinal stiffness, but not equally between lumbar levels.
基于设备的腰椎刚度测量具有识别更有可能通过脊柱手法治疗改善的腰痛患者的潜力。本研究评估了脊柱肌肉的自愿收缩如何影响刚度测量。
确定不同脊柱肌肉的收缩如何影响所有腰椎水平的脊柱刚度。
实验研究。
使用机械装置从 L1 到 L5 测量 12 名无症状参与者的脊柱刚度（N/mm），同时记录来自四对胸腰椎肌肉的肌肉活动。在参与者正常呼气时屏住呼吸收集基线测量值。然后，让参与者进行（1）等长髋关节伸展，（2）等长肩部屈曲和（3）深吸保持，测量其刚度。使用混合模型 ANOVA 评估这些扰动对每个腰椎水平的脊柱刚度的影响。然后计算 Friedman 检验以评估扰动之间肌肉活动的差异。
总体而言，设计的扰动以不同的幅度在不同的肌肉中产生活动（P 值≤0.05）。在髋关节伸展期间，每个脊柱水平的脊柱刚度均增加，在深吸保持期间，L5 的脊柱刚度增加（P 值<0.05）。在髋关节伸展和深吸保持期间，观察到脊柱水平对脊柱刚度的影响存在差异（P 值<0.05）。
本研究提供了证据表明肌肉活动的幅度会影响脊柱刚度，但在腰椎水平之间并不均匀。
