Comparisons of lumbosacral kinematics among non-specific chronic low back pain subgroups and healthy during prolonged sitting: A cross-sectional observational study.

BACKGROUND: The literature has suggested a variety of postural changes of the spine that possibly contribute to the increase in back pain during sitting in persons with non-specific chronic low back pain (NS-CLBP). However, the heterogeneity of NS-CLBP persons has made the ability to attribute pain increase to a particular sitting posture very difficult. Therefore, the purpose of this study was to compare lumbosacral kinematics and their roles in pain increase among homogenous NS-CLBP subgroups and healthy controls over a 1-h sitting period. METHODS: Twenty NS-CLBP subjects with motor control impairment [10 classified as having flexion pattern (FP) disorder, and 10 with active extension pattern (AEP) disorder], and 10 healthy controls participated in the study. Subjects underwent a 1-h sitting protocol on a standard office chair. Lumbosacral postures including sacral tilt, third lumbar vertebrae (L3) position, and relative lower lumbar angle were recorded using two-dimensional inclinometers over the 1-h period. Perceived back-pain intensity was measured using a visual analog scale every 10 min throughout the sitting period. RESULTS: All study groups (FP, AEP and healthy controls) significantly differed from each other in the measured lumbosacral kinematics at the beginning as well as at the end of the sitting period (p ≤ 0.05). Only the NS-CLBP subgroups showed significant changes in the lumbosacral kinematics across the 1-h sitting period (p < 0.01), and that the directions of change occurred toward end spinal postures (lumbar kyphosis for FP subgroup and lumbar lordosis for the AEP subgroup). In addition, both NS-CLBP subgroups reported a similarly significant increase in pain through mid-sitting (p < 0.001). However, after mid-sitting, the AEP subgroup reported much less increase in pain level that was accompanied by a significant decrease in the lumbar lordotic postures (p = 0.001) compared to FP subgroup. CONCLUSION: The present study's findings suggest that each NS-CLBP subgroup presented with differently inherent sitting postures. These inherently dysfunctional postures coupled with the directional changes in the lumbosacral kinematics toward the extreme ranges across the 1-h sitting period, might explain the significant increase in pain among subgroups.

Non-specific chronic low back pain and physical activity: A comparison of postural control and hip muscle isometric strength: A cross-sectional study.

Most research on sedentary lifestyle has focused on pain and disability, while neuromuscular outcomes (postural control and strength) have received less attention. The objective of the study was to determine whether low level of physical activity is negatively associated with measures of lower body muscular strength and postural control in individuals with and without non-specific chronic low back pain (NSCLBP).Twenty-four subjects with NSCLBP (28.8 ±â€Š5.9 years) and 24 age, gender, and body mass index matched healthy controls participated in the study. Subjects were sub-classified into 4 subgroups based on their physical activity level: Non-active NSCLBP; Active NSCLBP; Non-active healthy control; and Active healthy control. Each subgroup consisted of 12 subjects. Peak force of hip muscles strength was assessed using a handheld dynamometer. Postural control was assessed using computerized posturography and the Y Balance Test.There was no significant group by physical activity interaction for strength and static and dynamic postural control, except for static control during left single leg stance with eyes closed (P = .029). However, there was a significant difference in strength and postural control by physical activity (P < .05). Postural control and peak force of hip muscles strength were significantly associated with physical activity (r ranged from 0.50 to 0.66, P < .001 and r ranged from 0.40 to 0.59, P < .05, respectively).Postural control and hip strength were independently related to physical activity behavior. A sedentary behavior may be an important risk factor for impaired postural control and hip muscles strength, and that physical fitness is vital to neuromuscular outcomes.