Comparison of Biofeedback Tools to Train the Transversus Abdominis Activation in Healthy Subjects

Participants will be taught about the anatomy of abdominal wall muscles and the general functioning of RUSI (5 mins). Then, they will be invited to take the supine position, knees flexed. The feedback will consist of an ultrasound image transmitted to a brightness (B)-mode. Participants will receive the necessary education to understand the image and the desired recruitment according to a standardized protocol. They will then be asked to perform 15 contractions held 10 seconds of the TrA with a visible thickening of the TrA on the RUSI monitor exceeding the measurement at rest (visible on the monitor). Forty-five seconds rest will be allowed between each contraction to avoid fatigue. Participants will have to watch the RUSI monitor during the 15 tests.

Participants will receive the same instruction on the anatomy of abdominal wall muscles and general information about the PBU device. They will be invited to take the same position as for the RUSI group (supine, knees flexed). The feedback will be to visualize the intensity of pressure on the dial of a STABILIZER PBU (Chattanooga Group, Hixon, TN). Participants will receive the education necessary to understand the tool and the desired recruitment according to a standardized protocol. They will then be asked to perform 15 contractions of the TrA with a duration of 10 seconds while maintaining the constant pressure at 40 mmHg ± 2 mmHg. Forty-five seconds of rest will be allocated between each contraction. Participants will have to watch the PBU dial during the 15 tests.