Changes in thoracolumbar kinematics and centre of pressure when performing stationary tasks in moving environments

Wave induced platform motions observed in marine environments pose a significant risk to offshore workers' safety. While the strenuous and potentially dangerous nature of the many offshore occupations does play a role, the wave induced platform motions observed in marine environments and their effects on postural stability also contribute to this risk. The purpose of this study was to examine the effects of platform motions on thoracolumbar kinematics and foot centre of pressures during stationary standing and load holding tasks. Twelve participants (9 male, 3 female) completed two tasks in four distinct sea conditions. While performing these tasks, thoracolumbar kinematics and foot centre of pressures were measured using the Lumbar Motion Monitor and F-Scan foot pressure system, respectively. Thoracolumbar kinematics and foot centre of pressures measurements increased in magnitude as platform motion magnitudes increased. Furthermore, in tasks where the subject experienced a motion induced interruption dependent measurement magnitudes further increased. Results suggest that wave induced perturbations have a significant effect on biomechanical measures used to assess balance and stability during the performance of stationary standing and load holding activities. These measures suggest that the body is less stable while performing standing and holding tasks in moving environment, particularly as a change-in-support corrective strategy must be initiated regularly to maintain postural stability.