Training of transversus abdominis activation in the supine position with ultrasound biofeedback translated to increased transversus abdominis activation during upright loaded functional tasks.

OBJECTIVE

To determine whether healthy adults successfully completing transversus abdominis (TrA) muscle activation training in the supine position with clinician and ultrasound (US) imaging feedback increase their TrA activation during lifting and reaching tasks performed in the standing position.

DESIGN

Prospective longitudinal within-subject, repeated-measures (RM) study.

SETTING

University laboratory.

PARTICIPANTS

A total of 19 of 24 asymptomatic adult volunteers met inclusion criteria.

METHODS

Each adult performed 3 trials of 5 functional tasks before receiving any training. They were then briefed on the abdominal draw-in maneuver via educational materials. Next, each adult received individualized TrA activation training while in the supine position with clinician and US feedback of TrA activation. At 5 minutes after TrA activation training, each adult who met the criterion during training performed 3 trials of these same 5 functional tasks. Tasks were randomized during these test sessions. Adults who returned 5 months later (n = 10) were tested again on 3 trials of 3 of these tasks. No feedback was provided during test sessions. Recorded cine loop images were obtained via US per trial and masked for TrA measurement.

MAIN OUTCOME MEASUREMENTS

Resting state (minimum thickness) and contraction state (maximum thickness) of TrA were measured per recorded trial by a clinician who was shown to have high reliability. The percentage of change in TrA thickness {[(thicknessmax - thicknessmin)/ thicknessmin] × (100)} was the primary outcome measure. Trial averages were formed per measure per task per test session per adult.

RESULTS

A 2-test sessions (pretraining, 5-minutes post-training) × 5 tasks RM analysis of variance (N = 19) indicated a significant and large effect for test sessions (P < .001, η(2) = 0.808) and moderate effect for tasks (P = .011; η(2) = 0.164). Likewise, a 3-test sessions (pretraining, 5-minutes posttraining, 5 months post-training) × 3 tasks RM analysis of variance (n = 10) indicated a significant and large test sessions effect (P < .001, η(2) = 0.57) and no task effect. Overall, the percent change in TrA thickness increased after the TrA activation training program and was maintained at 5 months; similar patterns of improvement were noted across test sessions and tasks.

CONCLUSION

Asymptomatic adults successfully completing a short session of TrA activation training in the supine position with US feedback of TrA activation were able to increase their TrA activation during loaded lifting and reaching tasks for at least 5 months.