Trunk posture adaptations during sitting on dynamic stool: a validation study

Back pain is a complex condition that results from multiple factors including sitting issues such as the chair type and spinal sitting posture. The physiological spinal curvature on the sagittal plane represents a typical feature of good body posture. Sitting postures matching the physiological shape of the spine on the sagittal plane during standing are deemed advantageous from a postural point of view. The aim of this study was to validate a novel dynamic stool by comparing trunk posture adaptations on the sagittal plane during dynamic sitting vs. conventional sitting (standard stool) in healthy people. In total, 100 healthy adults were included. Age, sex and body mass index were recorded. Thoracic kyphosis and lumbar lordosis were measured with the IncliMed(R) goniometer during standing posture, conventional sitting posture (standard stool) and dynamic sitting posture (novel dynamic stool). Sitting posture was maintained for 2 min before evaluation. Thoracic kyphosis and lumbar lordosis were significantly different between standing vs. sitting (dynamic and conventional) posture (p < 0.001) and between dynamic vs. conventional sitting posture (p < 0.001). Sitting on the novel dynamic stool tested in this study was shown to provide a greater match of thoracic kyphosis and lumbar lordosis with the physiological spinal curvature on the sagittal plane during standing than conventional sitting.