Ultrasonography and Electromyography Activity of Abdominal Muscles in Different Abdominal Exercises: A Systematic Review.

Objective. The aim of this study was to systematically review current literature on the effectiveness of various exercises and modifications on thickness and electrical activity of abdominal muscles using ultrasonography and electromyography in healthy adults. Methods. An electronic search was carried out on PubMed, Web of science, ProQuest, Google Scholar, Cochrane and Science Direct databases covering published studies from inception until December 2022. Fourteen papers were then included according to following inclusion criteria: 1) studies assessing abdominal exercises; 2) containing control and intervention groups; 3) conducted on young and healthy samples; 4) full texts being available in English; 5) containing the analysis of at least one of the four abdominal muscles through electromyography or ultrasonography. Results. The main findings would suggest that stability challenges, rotatory exercise, combination of upper and lower limb movements, sensory cueing and grunting techniques such as Ki-hap make significant improvements in muscle structure and activity. Conclusions. Despite the averagely fair quality of included papers and difficulty to reach a conclusion with inadequate data, our review suggests that new modifications of both traditional and core exercises can cause improvements in abdominal muscle thickness or activity with the aim of focusing on control and coordination of muscles. Study registration. The protocol of the present systematic review is registered in the PROSPERO (CRD42022377864). [ABSTRACT FROM AUTHOR]