A kinematic and kinetic analysis of spinal region in subjects with and without recurrent low back pain during one leg standing

Abstract

Background: The purpose of this study was to evaluate the relationship between normalized kinematic and kinetic stability indices for spinal regions with eyes-open and eyes-closed conditions during non-dominant leg standing between subjects with recurrent low back pain and control subjects.

Methods: The kinematic stability index for the spinal regions (core spine model, lumbar spine, lower and upper thorax) and the kinetic stability index from force plate were measured. All participants were asked to maintain non-dominant leg standing with the dominant hip and knee flexed approximately 90 degrees for 25 seconds. Forty-two participants enrolled in the study, including 22 subjects with low back pain (12 male, 10 female) and 20 control subjects (12 male, 8 female).

Findings: For the kinematic index for stability, the visual condition (F=30.06, p=0.0001) and spinal region (F=10.82, p=0.002) were statistically significant. The post hoc test results indicated a significant difference in the lumbar spine compared with the upper and lower thorax and the core spine model. The kinetic stability (average [standard deviation]) during the eyes-closed condition significantly decreased in the low back pain group (t=-3.24, p=0.002).

Interpretation: The subjects with recurrent low back pain demonstrated higher lumbar spine stability in eyes-open condition. This higher stability of the lumbar spine might be due to a possible pain avoiding strategy from the standing limb. The low back pain group also significantly decreased kinetic stability during the eyes-closed condition. Clinicians need to consider both kinetic and kinematic indices while considering visual condition for lumbar spine stability in subjects with recurrent low back pain.

Keywords: Balance; Kinematics; Kinetics; Normalized stability; Recurrent low back pain; Vision.