Low back pain affects trunk as well as lower limb movements during walking and running.

Up to now, most gait analyses on low back pain concentrate on changes in trunk coordination during walking on a treadmill. Locomotion on uneven ground as well as lower limb changes receives little attention in association with low back pain. The present study focuses on how chronic non-specific low back pain causes modifications in lower limb and trunk movements, in level and uneven walking and running. We found that trunk as well as lower limb movement was influenced by chronic non-specific low back pain. A consistent finding across all gaits and ground level changes is that patients with chronic non-specific low back pain show less pelvis and unchanged thorax rotation as compared to healthy controls. Furthermore, in chronic non-specific low back pain patients the trunk rotation decreased only during level and uneven running whereas the sagittal trunk inclination at touchdown increased only during uneven walking as compared to healthy controls. Besides significant changes in the upper body, in chronic non-specific low back pain patients the knee joint angle at touchdown was more extended during level walking but also during uneven walking and running as compared to healthy controls. We assume that trunk movements interact with lower limb movements or vice versa. Therefore, we recommend that further investigations on low back pain should consider both trunk (primarily pelvis) and lower limb (primarily knee) movements.