Characteristics of trunk control during crook-lying unilateral leg raising in different types of chronic low back pain patients.

Abstract

Cross-sectional observational study. To quantitatively clarify the characteristics of trunk control during unilateral leg-raising movement in different types of nonspecific chronic low back pain (NS-CLBP) patients who were identified by aggravation of symptoms during trunk movement. Although there is a need to classify NS-CLBP patients for clinical decision making in physical therapy, the characteristics of trunk control during unilateral leg-raising movement in different types of NS-CLBP patients have not been quantitatively analyzed in previous studies by simultaneously measuring the lumbar spine movement, trunk muscle activity, and leg movement. Thirty NS-CLBP patients, of whom 13 were aggravated by trunk flexion (flexion group) and 17 were aggravated by trunk extension (extension group), and 30 healthy controls performed crook-lying unilateral leg-raising movement on the painful side in patient group and the dominant leg in controls. During the unilateral leg-raising movement, pressure changes produced by the movement of the lumbar lordotic curve, measured by a custom-made recording device, were used as indices of the lumbar spine movement. Trunk muscle activities were recorded by surface electromyography and diagnostic ultrasonography. The pressure changes and trunk muscle activities were statistically compared among the 3 groups. At foot-off during unilateral leg-raising movement, the extension group demonstrated increase in pressure changes, whereas the flexion group and controls demonstrated decrease in pressure changes. Bilateral external obliques muscle activities in the extension group were significantly larger than those in the flexion group and controls (P < 0.05). This study demonstrated that the characteristics of trunk control during unilateral leg-raising movement were different depending on the types of NS-CLBP patients. These results indicate that patients with NS-CLBP might select compensatory trunk control strategies subconsciously to prevent the manifestation of LBP. These results also suggest the importance of the different characteristics of trunk control during active limb movement in the clinical reasoning process for the management of different types of NS-CLBP patients. N/A.