Muscle Activity of Abdominal and Back Muscles during Six Starting Positions in Untrained Individuals
Sakulsriprasert, P.; Eak-udchariya, P.; Jalayondeja, W.
Journal of the Medical Association of Thailand 98(Suppl 5): S125-S130
2015
ISSN/ISBN: 0125-2208 PMID: 26387423 Document Number: 16680
This study aimed to investigate the electromyography (EMG) activity amongfive abdominal and back muscles at six starting positions in untrained individuals. Twenty-five healthy individuals aged 20.9 +/- 3.9 years, who were inexperienced with lumbar stabilization exercise, were recruited. They were asked to perform maximum voluntary isometric contraction (MVIC), and then six starting positions in random order EMG data ofeach starting position were normalized as a percentage of MVIC. Friedman two-way analysis of variance (ANOVA) and Wilcoxon signed-ranks tests were used for data analysis. Significant differences in EMG activity of five abdominal and back muscles were found in all six starting positions (p<0.001). The highest EMG activity ofthe transversus abdominis/internal abdominal oblique (TrA/IO) was found in crook lying, with right leg lifted (CLR), and of multifidus (MF) in four-point kneeling with straight right leg lifted horizontally (4p-SRL). The results suggested that CLR and sitting on a gym ball (SG) were able tofacilitate TrA/IO activity with minimal activity from the rectus abdominis (RA), while CL, 4p-SRL, andSG were able tofacilitate MF activity with minimal activity from erector spinae (ES).