Electromyographic Activity of the Rectus Abdominis Muscle during Physical Conditioning Exercises: A Systematic Review

Purpose: The rectus abdominis muscle is involved in support, containment of viscera, respiration, defecation, urination, vomiting, and assistance during delivery. Many exercises and equipment are used to strengthen the rectus abdominus muscle, which aim to prevent and rehabilitate low back pain, improve athletic performance, or achieve aesthetic standards. Exercises that potentiate electromyographic activity require the recruitment of the biggest number of muscle fibers and are more effective in developing or maintaining strength. Analysis of electromyographic activity allows us to determine the quality of physical exercises for strength training, and to choose and order them properly in a training session. This systematic review has been developed following the protocol registered in the International Prospective Review Record (PROSPERO) under number CRD42018086172. Methods: To identify relevant studies, we searched for articles in the following databases: MEDLINE, PubMed, Europubmed, SciELO, and Google Scholar. The methodological quality of the studies included in the review and the risk of bias were established based on the Cochrane Handbook of Systematic Reviews of Interventions. Results: After analysis of the full texts, 13 studies were considered eligible in the qualitative synthesis and were included for quantitative analysis. Conclusion: We conclude that electromyographic studies are required, with more rigorous methodological criteria, with the objective of reducing the risk of bias and obtaining definitive conclusions about muscle activity and identifying efficient exercises for the development of the rectus abdominis muscle strength. Ventral plank exercises present better electromyographic results for the rectus abdominis muscle and its action.