Hu Y, Wong Y L, Lu William W, Kawchuk Gregory N
Department of Orthopaedics, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam Road, Hong Kong.
Clin Biomech (Bristol). 2009 Dec;24(10):799-806. doi: 10.1016/j.clinbiomech.2009.07.013. Epub 2009 Aug 21.
Low back pain is often associated with increased spinal stiffness which thought to arise from increased muscle activity. Unfortunately, the association between paraspinal muscle activity and paraspinal stiffness, as well as the spatial distribution of this relation, is unknown. The purpose of this investigation was to employ new technological developments to determine the relation between spinal muscle contraction and spinal stiffness over a large region of the lumbar spine.
Thirty-two male subjects performed graded isometric prone right hip extension at four different exertion levels (0%, 10%, 25% and 50% of the maximum voluntary contraction) to induce asymmetric back muscle activity. The corresponding stiffness and muscle activity over bilateral paraspinal lumbar regions was measured by indentation loading and topography surface electromyography, respectively. Paraspinal stiffness and muscle activity were then plotted and their correlation was determined.
Data from this study demonstrated the existence of an asymmetrical gradient in muscle activation and paraspinal stiffness in the lumbar spine during isometric prone right hip extension. The magnitude and scale of the gradient increased with the contraction force. A positive correlation between paraspinal stiffness and paraspinal muscle activity existed irrespective of the hip extension effort (Pearson correlation coefficient, range 0.566-0.782 (P<0.001)).
Our results demonstrate the creation of an asymmetrical gradient of muscle activity and paraspinal stiffness during right hip extension. Future studies will determine if alterations in this gradient may possess diagnostic or prognostic value for patients with low back pain.
下背痛常与脊柱僵硬增加有关，这种僵硬被认为是由肌肉活动增加引起的。不幸的是，椎旁肌活动与椎旁僵硬之间的关联以及这种关系的空间分布尚不清楚。本研究的目的是利用新的技术发展来确定腰椎大区域内脊柱肌肉收缩与脊柱僵硬之间的关系。
32名男性受试者在四个不同的用力水平（最大自主收缩的0%、10%、25%和50%）下进行分级等长俯卧位右髋伸展，以诱发不对称的背部肌肉活动。分别通过压痕加载和表面肌电图测量双侧腰椎旁区域相应的僵硬程度和肌肉活动。然后绘制椎旁僵硬程度和肌肉活动的图表，并确定它们之间的相关性。
本研究数据表明，在等长俯卧位右髋伸展过程中，腰椎的肌肉激活和椎旁僵硬存在不对称梯度。梯度的大小和范围随收缩力增加。无论髋部伸展用力程度如何，椎旁僵硬程度与椎旁肌活动之间均存在正相关（皮尔逊相关系数，范围为0.566 - 0.782（P < 0.001））。
我们的结果表明，在右髋伸展过程中会产生肌肉活动和椎旁僵硬的不对称梯度。未来的研究将确定这种梯度的改变是否可能对下背痛患者具有诊断或预后价值。
