Activation of the Rectus Abdominis During Activities of Daily Living and Therapeutic Exercise

Abstract

0251 Approximately 15 million persons underwent some type of abdominal surgery in the United States in 2000, the majority being digestive and obstetrical procedures. Current recommendations for post surgical activity are typically avoidance of “strenuous” activity for 6–8 weeks to allow for wound healing and prevent dehiscence. Misinterpretation of this recommendation often results in minimal physical activity. The numerous deleterious effects of reduced physical activity have been well documented. It is unknown to what extent the Upper Rectus Abdominus (URA) and Lower Rectus Abdominus (LRA) are activated during activities of daily living (ADL) and how this activation compares to activation during cardiovascular exercises (CV), muscular strengthening exercises (MS), and controlled valsalva maneuvers (VM). PURPOSE: To quantify and compare the percent of surface electromyography (sEMG) activation amplitude of the upper and lower rectus abdominis during ADL, CV, MS, and VM. METHODS: Twenty-five healthy (13 women, 12 men; mean age, 36.5 ± 13.2 yr) subjects performed a maximal voluntary contraction (MVC) and 13 activities from four categories; ADL, MS, CV, and VM. The maximum root mean square (RMS) value for the URA and LRA signals over the duration of each task was identified and normalized to a percent of the MVC RMS. A two-way ANOVA with repeated measures (rectus abdominis by ADL) was performed to determine which ADL exhibited the greatest URA and LRA activity. This ADL task was then used as a reference. A two-way ANOVA with repeated measures (rectus abdominis by exercise) was performed to determine whether CV, MS, or VM produced greater sEMG activity as compared to the reference ADL. Tukey HSD test was performed for post hoc analysis. Significance was set at p<0.05. RESULTS: The rectus abdominis sEMG activity was significantly greater during the independent supine to sit task than all other tasks except the abdominal crunch. The URA elicited significantly greater sEMG activity than the LRA during all ADL, CV, MS, and VM tasks. CONCLUSIONS: The findings of the study suggest that the current practice of limiting post surgical activity should be re-examined.