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

ObjectivesTo assess abdominal muscles (AM) activity during prone, side, and supine bridge on stable and unstable surfaces (BOSU, Swiss Ball).DesignProspective comparison study.SettingResearch laboratory.ParticipantsThirty-three healthy volunteers from a university population.Main outcome measuresSurface electromyography of the rectus abdominis (RA), the external oblique (EO) and the internal oblique with the transversus abdominis (IO-TA).ResultsThe 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.ConclusionsThe 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.