Occupational Health and Safety Research Institute Robert-Sauvé, Montreal, Quebec, Canada.
Spine (Phila Pa 1976). 2010 Oct 15;35(22):E1178-86. doi: 10.1097/BRS.0b013e3181e53334.
An experimental and comparative study of chronic low back pain (CLBP) patients and healthy controls.
To use a motivation-independent electromyography (EMG) based test of back muscle capacity to determine whether back muscle deconditioning is present in CLBP patients and whether it is related to pain-related psychological variables.
The verification of the deconditioning syndrome in CLBP patients might be biased by the use of performance-based measures to assess physical fitness, especially in patients having fear of injury. Also, the use of lumbar-specific measures of physical fitness, such as back muscle strength and endurance, might be more sensitive to physical deconditioning than more general assessments such as aerobic capacity.
A time-limited submaximal fatigue test was performed by 27 nonspecific CLBP subjects (14 men) who had not had any surgery, and 31 healthy controls (17 men) while surface EMG signals were collected from back muscles. Motivation-independent EMG indices, which are sensitive to muscle fatigue or to activation patterns, were then computed and entered as input into previously developed regression equations to predict endurance (PTend) and strength (PStrength). Between-group comparisons were completed with patients divided in subgroups based on a median split of pain intensity, fear of movement, or pain catastrophizing scores.
Differences between healthy and CLBP subgroups were mainly observed when patients were divided using pain catastrophizing scores (PCS). High-PCS patients showed significantly lower PTend than low-PCS patients. Various EMG indices showed comparable results to PTend. However, some of them also pointed out that the PCS-low patients were more fatigue-resistant and showed different activation patterns comparatively to healthy subjects.
These results suggest that physical deconditioning that is specific to back muscle capacity was present in a subgroup of patients while the opposite was observed in another subgroup, pain catastrophizing being related to this outcome. These findings support previous theoretical models of pain/disability.
慢性下背痛（CLBP）患者与健康对照组的实验性和对照研究。
使用基于动机的肌电图（EMG）测试来确定慢性下背痛患者是否存在背部肌肉失能，以及它是否与疼痛相关的心理变量有关。
在 CLBP 患者中验证失能综合征可能会因使用基于表现的措施来评估身体健康而产生偏差，尤其是在有受伤恐惧的患者中。此外，使用腰椎特定的身体健康措施，如背部肌肉力量和耐力，可能比更一般的评估（如有氧能力）更敏感地反映身体失能。
对 27 名非特异性 CLBP 受试者（14 名男性）和 31 名健康对照组（17 名男性）进行限时亚最大疲劳测试，同时从背部肌肉收集表面 EMG 信号。然后计算出与肌肉疲劳或激活模式敏感的无动机 EMG 指数，并将其作为输入输入到先前开发的回归方程中，以预测耐力（PTend）和力量（PStrength）。通过将患者根据疼痛强度、运动恐惧或疼痛灾难化评分的中位数进行分组，将患者分为亚组，然后完成组间比较。
当根据疼痛灾难化评分（PCS）对患者进行分组时，健康组和 CLBP 亚组之间的差异主要观察到。高 PCS 患者的 PTend 明显低于低 PCS 患者。各种 EMG 指数与 PTend 具有类似的结果。然而，其中一些指数还指出，与健康受试者相比，PCS-低患者的抗疲劳能力更强，表现出不同的激活模式。
这些结果表明，在一个亚组患者中存在特定于背部肌肉能力的身体失能，而在另一个亚组患者中则相反，疼痛灾难化与这种结果有关。这些发现支持疼痛/残疾的先前理论模型。
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