Fig 1.
The standing trunk flexion and re-extension task.
Fig 2.
The approximate positioning of the EMG grid and accelerometer.
The EMG electrode grid was placed 3 cm lateral to the lumbar spinous process on the bilateral erector spinae. The accelerometer was placed at the 12th thoracic spinous process.
Table 1.
Baseline values of each variable’s ‘poor’ and ‘good’ groups.
Fig 3.
The differences in the topographical maps of the RMS value between the low-FRR and high-FRR groups.
Representative topographical maps of the electromyographic RMS values recorded from the bilateral erector spinae for a high-FRR patient and a low-FRR patient in the standing phase, flexion phase, full flexion phase, and extension phase of the standing forward bending task. Blue indicates low muscle activity, and yellow indicates high muscle activity. The RMS values of the low-FRR patient were lower than those of the high-FRR patients in the standing phase and full flexion phase. The RMS value of each channel was insert in topographical maps. The changes in the RMS value between the flexion phase and the full flexion phase in the low-FRR patients were smaller compared to those of the high-FRR patients.
Fig 4.
The difference in the y-coordinate of the centroid between the low-variability and high-variability groups.
The mean (±SD) of the y-axis coordinate of the centroid of the RMS map estimated in the standing phase, flexion phase, full flexion phase, and extension phase of the standing forward bending task. The high-variability group tended to show greater changes in the y-coordinate of the centroid compared to the low-variability group.
Table 2.
Association rules sorted by lift value (Consequent = RMDQ high).
Table 3.
Association rules sorted by lift values (Consequent = RMDQ low).
Fig 5.
Association rules: A graphic view related to high RMDQ scores.
The rules of severe CLBP disability were divisible into (A) low FRR-related rules, (B) high HADS depression-related rules, (C) high TSK and NRS fear-related rules, (D) high CSI-related rules, and (E) high PCS-related rules.
Table 4.
Association rules: Antecedent = included two variables, consequent = RMDQ high, minimum confidence = 80%.
Fig 6.
Association rules: A graphic view related to low RMDQ.
The rules of mild CLBP disability were divisible into (A) high FRR-related rules, (B) low FreBAQ-related rules, (C) low HADS depression-related rules, and (D) high variability-related rules.
Table 5.
Association rules: Antecedent = included two variables, consequent = RMDQ low, minimum confidence = 80%.