BridGE: A New System to Train Selective Pelvis Movements

Background: Sitting balance is an important target in motor rehabilitation and injury prevention as poor sitting posture can induce musculoskeletal problems affecting life quality. Exercises to improve core stability like strengthening specific muscles of the low-back or of the pelvic floor performing selective pelvic movements exercises have been suggested to improve sitting balance promoting an efficient interaction between spine, pelvis, and the entire kinematic chain. It is in this framework and with such aim that we developed a new device BridGE and we preliminary tested it with healthy subjects. Methods: BridGE is a sensorized balance board with two IMUs, one inside the balance board and one on the trunk of the subject that is sitting on it, for training selected pelvis movements while monitoring the trunk position. Subjects performed various tasks controlling vertical and horizontal movement of a cursor on a screen with two distinct pelvic movements: lateral tilt and antero-posterior tilt. During practice we also monitored the trunk tilt as the request was to maintain the trunk as still as possible, to decouple trunk and pelvis movements. Results: After training with BridGE subject had significant improvements in pelvic movements and in trunk posture decreasing trunk undesired movements and increasing the isolation of the pelvis tilts in the antero-posterior and right-left directions. Conclusions: This is a first proof of concept that BridGE is an effective low-cost tool to train selective movements of the pelvis avoiding unnecessary trunk compensatory movements and, in the future, could be a useful tool for sitting balance rehabilitation.