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Trunk muscle activity in healthy subjects during bridging stabilization
exercises.
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.
Background
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 stabilization exercises.
Methods
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 both sides.
Results
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.
Conclusion
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.

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