Abdominal muscle EMG-activity during bridge exercises on stable and unstable surfaces

Objectives: To assess abdominal muscles (AM) activity during prone, side, and supine bridge on stable and unstable surfaces (BOSU, Swiss Ball). Design: Prospective comparison study. Setting: Research laboratory. Participants: Thirty-three healthy volunteers from a university population. Main outcome measures: Surface electromyography of the rectus abdominis (RA), the external oblique (EO) and the internal oblique with the transversus abdominis (IO-TA). Results: The AM exhibited the highest activity during prone bridge on a Swiss Ball (RA, EO, IO-TA 44.7 +/- 19.2, 54.7 +/- 22.9, 36.8 +/- 18.6 in % of MVC, respectively). The lowest activity was observed during supine bridge on a stable surface and a BOSU (under 5.0). The lowest ratio analyzed on the basis of the relation of EO and IO-TA activity to RA was obtained during prone bridge on the Swiss Ball (1.4 +/- 0.7 for EO, 0.9 +/- 0.5 for IO-TA). The highest ratio was obtained during prone bridge on stable surface and supine bridges. Conclusions: The highest level of activity in the abdominal muscles is achieved during prone bridge on a Swiss Ball. However, this exercise provided the lowest activity of the EO and IO-TA in relation to RA. It is essential to conduct further studies verifying the usefulness of using Swiss Ball during core stability training. (C) 2013 Elsevier Ltd. All rights reserved.