Multi-segment kinematic model to assess three-dimensional movement of the spine and back during gait

Background: Relatively little is known about spine during gait compared to movement analysis of the lower extremities. The trunk is often regarded and analysed as a single rigid segment and there is a paucity of information on inter-segmental movement within the spine and its relationship to pelvis and lower limbs. Objectives: To develop and validate a new multi-segment kinematic model to assess regional three-dimensional movement of the lumbar, lower thoracic and upper thoracic spine during gait. Study design: Observational study. Methods: The study was conducted in two parts: (1) to provide validation measures on the kinematic model built in commercially available software and (2) to apply the marker configuration to the spine at T3, T8 and L3 during gait analysis on 10 healthy male volunteers. Results: Proposed model revealed excellent concurrent validation measures between an applied input angle to the recorded output angle from the kinematic model. A high reliability was observed during gait analysis, both during a single session and between sessions for all participants. Conclusion: The thoracic region of the spine should not be modelled as a single rigid segment and the proposed three-dimensional cluster is reliable and repeatable to assess the inter-segmental movement of the spine. Clinical relevance Reliable kinematic data can be collected using the three-dimensional cluster technique, thus, allowing researchers to accurately distinguish between movement patterns of healthy individuals to those with a clinical condition, and provide confidence in data acquisition during the monitoring process of an implemented rehabilitation intervention programme.