Center for Sensory-Motor Interaction, Department of Health Science and Technology Faculty of Medicine, Aalborg University, Aalborg, Denmark.
Exp Brain Res. 2011 Apr;210(2):259-67. doi: 10.1007/s00221-011-2629-8. Epub 2011 Mar 26.
The purpose of this study was to assess the activation of the erector spinae (ES) and external oblique (EO) in response to unanticipated, bi-directional postural perturbations before and after the induction of acute low back pain (LBP) in healthy individuals. An experimental session consisted of a baseline, control, and an acute LBP condition. For the control and acute LBP condition, isotonic or hypertonic saline (HS), respectively, was injected into the right ES muscle. In each condition, participants stood on a moveable platform during which 32 randomized postural perturbations (8 repetitions of 4 perturbation types: 8 cm anterior slides, 8 cm posterior slides, 10° anterior tilts, and 10° posterior tilts) with varying inter-perturbation time intervals were performed over a period of 4-5 min. Bilateral surface electromyography (EMG) was recorded from the ES and EO in addition to subjective pain records. During the acute LBP condition: (1) the onset time of the ES and EO was delayed for the forward and backward sliding perturbations (P < 0.05); (2) EMG amplitude was reduced bilaterally for all perturbations (P < 0.05); (3) the order of activation and interval between the onset times of the ES and EO were unaltered and (4) ES, but not EO, activity was adjusted to account for the directional differences between the perturbations. This study revealed that re-establishment of posture and balance was a result of the individuals' ability to rapidly modulate ES with respect to EO activity and that the bi-directional postural responses, although shifted in time and amplitude, retained temporal features in the presence of acute LBP.
本研究旨在评估健康个体在急性腰痛（LBP）发作前后，对突发的双向姿势扰动，竖脊肌（ES）和腹外斜肌（EO）的激活情况。实验分为基线、对照和急性 LBP 三个条件。在对照和急性 LBP 条件下，分别向右侧 ES 肌肉注射等渗或高渗盐水（HS）。在每种条件下，参与者均站在可移动平台上，平台会在 4-5 分钟的周期内执行 32 次随机的姿势扰动（4 种扰动类型的 8 次重复：8cm 前滑、8cm 后滑、10°前倾和 10°后倾，每次扰动之间的间隔时间不同）。在 ES 和 EO 双侧记录表面肌电图（EMG），并记录主观疼痛记录。在急性 LBP 条件下：（1）ES 和 EO 的起始时间因前向和后向滑动扰动而延迟（P<0.05）；（2）所有扰动的双侧 EMG 幅度均降低（P<0.05）；（3）激活顺序和 ES 与 EO 起始时间之间的间隔保持不变；（4）ES 但不是 EO 活动被调整以适应扰动之间的方向差异。本研究表明，姿势和平衡的重新建立是个体快速调节 ES 相对于 EO 活动能力的结果，并且尽管在时间和幅度上存在双向姿势反应，但在急性 LBP 存在的情况下仍保留了时间特征。
