Graduate School of Arts and Sciences, Department of Life Sciences, The University of Tokyo, Tokyo, Japan.
Department of Physical Therapy, Tokyo University of Technology, Tokyo, Japan.
J Neuroeng Rehabil. 2023 May 31;20(1):69. doi: 10.1186/s12984-023-01190-z.
Chronic low back pain (CLBP) is a highly prevalent disease with poorly understood underlying mechanisms. In particular, altered trunk muscle coordination in response to specific trunk tasks remains largely unknown.
We investigated the muscle synergies during 11 trunk movement and stability tasks in 15 healthy individuals (8 females and 7 males, aged 21. 3 (20.1-22.8) ± 0.6 years) and in 15 CLBP participants (8 females and 7 males, aged 20. 9 (20.2-22.6) ± 0.7 years) by recording the surface electromyographic activities of 12 back and abdominal muscles (six muscles unilaterally). Non-negative matrix factorization was performed to extract the muscle synergies.
We found six trunk muscle synergies and temporal patterns in both groups. The high similarity of the trunk synergies and temporal patterns in the groups suggests that both groups share the common feature of the trunk coordination strategy. We also found that trunk synergies related to the lumbar erector spinae showed lower variability in the CLBP group. This may reflect the impaired back muscles that reshape the trunk synergies in the fixed structure of CLBP. Furthermore, the higher variability of trunk synergies in the other muscle regions such as in the latissimus dorsi and oblique externus, which were activated in trunk stability tasks in the CLBP group, represented more individual motor strategies when the trunk tasks were highly demanding.
Our work provides the first demonstration that individual modular organization is fine-tuned while preserving the overall structures of trunk synergies and temporal patterns in the presence of persistent CLBP.
慢性下腰痛（CLBP）是一种高发疾病，其潜在机制尚不清楚。特别是，针对特定的躯干任务，躯干肌肉协调性的改变在很大程度上仍不为人知。
我们在 15 名健康个体（8 名女性和 7 名男性，年龄 21.3（20.1-22.8）±0.6 岁）和 15 名 CLBP 参与者（8 名女性和 7 名男性，年龄 20.9（20.2-22.6）±0.7 岁）中进行了 11 项躯干运动和稳定性任务，记录了 12 个背部和腹部肌肉（每侧 6 个肌肉）的表面肌电图活动。通过非负矩阵分解提取肌肉协同作用。
我们在两组中都发现了六个躯干肌肉协同作用和时间模式。两组之间的躯干协同作用和时间模式高度相似，表明两组都具有躯干协调策略的共同特征。我们还发现，与腰椎竖脊肌相关的躯干协同作用在 CLBP 组中具有较低的可变性。这可能反映了 CLBP 中固定结构的背部肌肉受损，重塑了躯干协同作用。此外，在 CLBP 组中，在躯干稳定性任务中被激活的其他肌肉区域（如背阔肌和外斜肌）的躯干协同作用的可变性更高，这代表了当躯干任务要求较高时，更多的个体运动策略。
我们的工作首次证明，在持续存在的 CLBP 中，个体模块化组织是精细调整的，同时保持了躯干协同作用和时间模式的整体结构。
