Trunk muscle activity in healthy subjects during bridging stabilization
BMC Musculoskelet Disord.
2006; 7: 75.
Stevens VK, Bouche KG, Mahieu NN, Coorevits PL, Vanderstraeten GG, Danneels LA.
Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and
Health Sciences, Ghent University, Belgium.
Trunk bridging exercises
are often used as therapeutic exercises for lumbopelvic stabilization. These
exercises focus on the retraining of muscle coordination patterns in which
optimal ratios between local segmental stabilizing and global torque producing
muscle activity are assumed to be essential. However, a description of such
ratios is lacking. The purpose of this study was to investigate both relative
(as a percentage of maximal voluntary isometric contraction) muscle activity
levels and ratios of local to global muscle activity, during bridging
Thirty healthy university
students (15 men, 15 women) with a mean age of 19.6 year volunteered to perform
3 bridging exercises (single bridging, ball bridge and unilateral bridging). The
surface electromyographic activity of different trunk muscles was evaluated on
During all bridging exercises,
the ratio of the internal oblique to the rectus abdominis was very high due to
minimal relative activity of the rectus abdominis. In general, the ratio of the
internal/external abdominal oblique activity was about 1. However, during the
unilateral bridging exercise, the ipsilateral internal/external abdominal
oblique activity ratio was 2.79 as a consequence of the significant higher
relative activity of the internal oblique compared to the external oblique. The
relative muscle activity and the ratios of the back muscles demonstrated similar
activity levels for all back muscles, resulting in ratios about 1.
Both the minimal relative
activity of the rectus abdominis and the high internal oblique to the rectus
abdominis activity ratio reported in the present study are in accordance with
results of other trunk stabilization exercises. The relative muscle activity and
the ratio of the abdominal obliques seem to alter depending on the task and the
presumable need for stability. The findings concerning the relative muscle
activity and the ratios of the back muscles support the assumption that during
these bridging exercises, all back muscles contribute in a similar way to
control spine positions and movements in a healthy population.