The importance of trunk movement in human gait has been established by many studies. However, these investigations have examined trunk/pelvis motion or the pelvic/thoracic motion in isolation to lower limb kinematics. Studies quantifying spinal deformities and the range of spinal and trunkal movement have concentrated on spinal/back movement, with the subject performing tasks, such as flexion, while maintaining a static position. There is also a paucity of data detailing the real relative motion between the back and lower limb during gait, an important consideration when testing the Nottingham ‘flag-pole’hypothesis for spinal curvature generation.

Research into the use of opto-electronic gait analysis systems to measure dynamic back movements has shown the capability of these systems in producing repeatable patterns of back movements. While using a motion analysis system, if a relationship between the spinal movement and lower limb kinematics could be established, such a relationship would provide a new opportunity for range of movement studies in conditions like scoliosis. Furthermore, establishing such a relationship would allow investigation into the influence of one segment over another during locomotion.

This present study has examined the movement of markers placed on the back and pelvis, used in three-dimensional opto- electronic systems for gait studies, in relation to the markers placed on the lower limbs. The results of a pilot study have highlighted relative movements between various segments in simple tasks like flexion, lateral bending and negotiating steps, which have implications for spinal deformity generation. The findings also demonstrate the points to be considered in order to define dynamic trunk and spinal movement. Further ongoing studies are being undertaken to validate the findings.