Abdominal Muscle Recruitment in Adults With And Without Cystic Fibrosis
Creators: name: Taillon-Hobson, Anne
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2010
Subjects: subject: Health Sciences, Recreation.

description: The electromyographical (EMG) of the superficial and deep abdominal muscle activity during voluntary and automatic tasks has been well researched, particularly in the normal population as well as individuals with low back pain and more recently in individuals with stress urinary incontinence. Two common normalization procedures used to reference the test data are the percent of maximum contraction (%MVC) and the double straight-leg-raise (dSLR). No EMG study to date has included participants with a pulmonary disease such as cystic fibrosis, who also have a high prevalence of low back pain and stress urinary incontinence. Therefore the purpose of this study was to investigate the recruitment patterns of the superficial and deep abdominal muscles in individuals with stable cystic fibrosis. The two primary objectives of this study were: i) to compare the electromyographic (EMG) activity of four abdominal muscles (the upper and middle fibers of rectus abdominus (RA-UP and RA-MID respectively) the obliquus externus (EO), and the obliquus internus/tranversus abdominus (IO/TrA) group during the abdominal hollowing exercise (AH)) and the unilateral leg 10ad"(ULL)) between a group of participants with stable cystic fibrosis and a gender-matched control group and ii) to compare the EMG muscle activity of the superficial and the deep abdominal muscles across and within the AH and the ULL tasks. A secondary objective was to compare the study's results when using two different normalization techniques: the %max-referenced contractions and %dSLR-referenced contractions. METHODS: Twenty-eight adults (14 with stable CF and 14 controls) performed (i) the AH exercise to three motor target pressures (42mmHg, 50mmHg, and 55mmHg) using a pressure biofeedback unit (PBU) and (ii) a right-leg ULL. Bipolar surface electrodes were used to record the EMG data. Two types of reference contractions (percent of maximum voluntary contraction (%max) and the double straight-leg-raise (dSLR)) were used to normalize the data. RESULTS: A 3--way ANOVA indicated no difference between the groups, but a significant muscle*task interaction was found. Post-hoc Bonferonni tests on pooled data revealed significant differences between the mean EMG amplitudes of the superficial and the deep abdominal muscles during all of the abdominal hollowing exercises as well as an increase in superficial abdominal muscle activity as the abdominal hollowing task became more difficult. No group differences were found in the ULL activity but significant differences were found between the superficial and deep muscles. The conclusions were the same regardless of the normalization procedure. DISCUSSION: The results from this study demonstrate that individuals with stable CF do not present with over-activity of the superficial abdominal muscles or inhibition of the deep abdominal muscles as compared to a control group. The EMG patterns and intensities found here support those of previous studies and could serve as normative data for future studies involving both CF and control group participants who are symptomatic of low back pain or stress urinary incontinence.