Changes in lumbar movement in people with low back pain are related to compromised balance

Abstract

Study Design: Comparing people with and without low back pain (LBP). Objectives. This study aimed to investigate lumbar spine movement and the quality of postural recovery in response to unexpected postural perturbation in people with LBP. Summary of Background Data. People with chronic LBP tend to use lumbar spine motion less frequently for postural control than pain-free individuals, and after voluntary arm movement, they need more time and a greater number of postural adjustments to regain postural equilibrium. We hypothesize that motion of the lumbar spine is altered in people with chronic LBP, and this would be associated with compromised control of postural stability in response to unexpected perturbation. Methods. The response to a sudden load imposed by a weight dropped into a box held in the hands was studied in 11 individuals with chronic LBP and matched controls. Lumbopelvic motion was recorded with an electromagnetic motion analysis system. Time to recover balance was calculated from ground reaction forces. Results. People with LBP had a delayed initiation of lumbar spine flexion (angular displacement) (Control = 44.9 [25.1] ms, LBP = 90.2 [42.3] ms, P < 0.001) and took longer to regain postural stability (Control = 460.4 [123.4] ms, LBP = 761.0 [194.2] ms, P < 0.001) after the perturbation. Conclusion. These data provide further evidence that the quality of balance control is compromised in LBP patients and that this is associated with poor use of spinal motion as a component of the postural strategy.