Kinematic analyses of trunk stability in one leg standing for individuals with recurrent low back pain.

This prospective study examined normalized stability differences based on dominance side and visual feedback. Subjects with low back pain (LBP) (n=26; 9 men, 17 women) and without LBP (n=28; 11 men, 17 women) participated in this study. All subjects were asked to maintain single leg standing balance with the contralateral hip flexed 90° for 25s. The outcome measures included normalized holding duration and stability. The combined rotation (R(xyz)) was also calculated to compare the upper and lower thorax and lumbar axes relative to the core spine axis. The holding duration was significantly different between groups (T=-2.21, p=0.03). The subjects without recurrent LBP (control group) demonstrated longer hold duration times (24.60±4.2s) than the subjects with recurrent LBP (21.2±7.1s). For the normalized hold duration, there was a significant difference between groups based on visual input (F=7.13, p=0.009). There was also a significant difference in standing stability based on visual input (F=93.93, p=0.0001) and trunk area (F=101.51, p=0.0001). In addition, the normalized stability was significantly different based on dominance and visual input (F=11.28, p=0.002). Therefore, trunk stability could prompt an uncoordinated bracing effect with poor proprioception from injury to passive structures or due to interference of pain during central processing of information in subjects with recurrent LBP.