Low back pain status affects pelvis-trunk coordination and variability during walking and running.

BACKGROUND: The purpose of this study was to compare pelvis-trunk coordination and coordination variability over a range of walking and running speeds between three groups of runners; runners with low to moderate low back pain; runners who had recovered from a single bout of acute low back pain; and runners who had never experienced any symptoms of low back pain.

METHODS: Pelvis and trunk kinematic data were collected as speed was systematically increased on a treadmill. Coordination between pelvis and trunk in all three planes of motion was measured using continuous relative phase, and coordination variability was defined as the standard deviation of this measure.

FINDINGS: Oswestry Disability Index indicated the low back pain group was high functioning (mean 7.9% out of 100%). During walking, frontal plane coordination was more in-phase for the low back pain group compared to controls (P=0.029), with the resolved group showing an intermediate coordination pattern (P=0.064). During running, both low back pain (P=0.021) and resolved (P=0.025) groups showed more in-phase coordination in the transverse plane than the control group. The low back pain group also showed reduced transverse plane coordination variability compared to controls (P=0.022).

INTERPRETATION: Coordination and coordination variability results showed a continuum of responses between our three groups. Taken together, the data lend insight into increased injury risk and performance deficits associated with even one bout of low back pain, and suggest that clinicians need to look beyond the resolution of pain when prescribing rehabilitation for low back pain.