Effects of seat-thigh contact on kinematics performance in sit-to-stand and trunk flexion tasks

Results showed that kinematic performances (maximal antero-posterior and vertical center of mass velocity and maximal backward displacement of center of pressure) in both motor tasks were higher in 30-IFC than in 100-IFC. In the sit-to-stand task, time of seat-off is shorter in 30-IFC. As the subject's initial global posture was comparable across the experimental conditions, it can be discarded as a source of performance change. It is discussed that it is the enhanced pelvis mobility induced by the sitting condition which is responsible for the increase of motor performance in both trunk flexion and sit-to-stand tasks. Our results highlight the role of joint mobility in motor performance.