Effect of modified bridge exercise on trunk muscle activity in healthy adults a cross sectional study

Design: This is a cross-sectional study. Setting: University research laboratory. Participants: Fifteen healthy adults (mean age: 27.47 years) volunteered for this study. Intervention: The individuals performed standard bridge exercise and modified bridge exercises with right leg-lift (single-leg-lift bridge exercise, single-leg-lift bridge exercise on an unstable surface, and single-leg-lift hip abduction bridge exercise). Main outcome measures: During the bridge exercises, electromyography of the rectus abdominis, internal oblique, erector spinae, and multifidus muscles was recorded using a wireless surface electromyography system. Two-way repeated-measures analysis of variance (exercise by side) with post hoc pairwise comparisons using Bonferroni correction was used to compare the electromyography data collected from each muscle. Results: Bilateral internal oblique muscle activities showed significantly greater during single leg-lift bridge exercise (95% confidence interval: right internal oblique=- 8.99 to -1.08, left internal oblique = -6.84 to -0.10), single-leg-lift bridge exercise on an unstable surface (95% confidence interval: right internal oblique= -7.32 to -1.78, left internal oblique= -5.34 to -0.99), and single-leg-lift hip abduction bridge exercise (95% confidence interval: right internal oblique = -17.13 to -0.89, left internal oblique= -8.56 to -0.60) compared with standard bridge exercise. Bilateral rectus abdominis showed greater electromyography activity during single-leg-lift bridge exercise on an unstable surface (95% confidence interval: right rectus abdominis -9.33 to -1.13, left rectus abdominis=-4.80 to -0.64) and single-leg-lift hip abduction bridge exercise (95% confidence interval: right rectus abdominis= -14.12 to -1.84, left rectus abdominis= -6.68 to -0.16) compared with standard bridge exercise. In addition, the right rectus abdominis muscle activity was greater during single-leg-lift hip abduction bridge exercise compared with single-leg-lift bridge exercise on an unstable surface (95% confidence interval = -7.51 to -0.89). For erector spinae, muscle activity was greater in right side compared with left side during all exercises (95% confidence interval: standard bridge exercise = 0.19-4.53, single-leg-lift bridge exercise= 0.24-10.49, single-leg-lift bridge exercise on an unstable surface = 0.74-8.55, single-leg-lift hip abduction bridge exercise =0.47-11.43). There was no significant interaction and main effect for multifidus. Conclusions: Adding hip abduction and unstable conditions to bridge exercises may be useful strategy to facilitate the co-activation of trunk muscles. (C) 2017 Associacao Brasileira de Pesquisa e Pos-Graduacao em Fisioterapia. Published by Elsevier Editora Ltda. All rights reserved.