Comparison of abdominal hollowing and bracing practices on the transverse abdominis muscle thickness in young women with non-specific low back pain

  Introduction: Patients with low back pain usually suffer from reduction in the thickness of their transverse abdominis muscle. The purpose of this study was to compare the effect of abdominal hollowing and bracing practices on the transverse abdominis muscle thickness in the population of the young women with non-specific low back pain .   Materials and Methods: This study was a randomized-controlled clinical trial conducted in two groups of 60 women altogether (control and experimental) with recurrent non-specific low back pain. Subjects in the experimental group were randomly assigned to either perform abdominal hollowing or abdominal bracing. Exercises were performed 3 times a day, with 10 repeats for 6 weeks. Transverse abdominis muscle thickness was measured on both right and left sides, using ultrasonography, before and after six weeks of practice. Percent of ratio of changes in the transverse abdominis muscle thickness during contraction was also measured .   Results : The result of one way ANOVA test revealed no significant difference between the changes of mean percent of transverse abdominal muscle thickness during the hollowing and bracing practices on both right and left sides (P=0.21) . Conclusion: Although there was no statistically significant difference between the two practices mentioned, the mean percent of changes in the transverse abdominis muscle thickness ratio during abdominal bracing was greater than that during the hollowing practice. This latter finding may warrant more consideration in prospective clinical studies .