José M. Oliva-Lozano 1 and José M. Muyor 1,2,
1 Health Research Centre, University of Almería, 04120 Almería, Spain;
2 Laboratory of Kinesiology, Biomechanics and Ergonomics (KIBIOMER Lab.), Research Central Services,
University of Almería, 04120 Almería, Spain
* Correspondence:
Received: 14 May 2020; Accepted: 11 June 2020; Published: 16 June 2020
Abstract: The aim of this study was to systematically review the current literature on the
electromyographic (EMG) activity of six core muscles (the rectus abdominis, the internal and
external oblique, the transversus abdominis, the lumbar multifidus, and the erector spinae) during
core physical fitness exercises in healthy adults. A systematic review of the literature was conducted
on the Cochrane, EBSCO, PubMed, Scopus, and Web of Science electronic databases for studies from
January 2012 to March 2020. The Preferred Reporting Items for Systematic Reviews and Metaanalyses (PRISMA) guidelines were used. The inclusion criteria were as follows: a) the full text
available in English; b) a cross-sectional or longitudinal (experimental or cohorts) study design; c)
the reporting of electromyographic activity as a percentage of maximum voluntary contraction (%
MVIC), millivolts or microvolts; d) an analysis of the rectus abdominis (RA), transversus abdominis
(TA), lumbar multifidus (MUL), erector spinae (ES), and the internal (IO) or external oblique (EO);
e) an analysis of physical fitness exercises for core training; and f) healthy adult participants. The
main findings indicate that the greatest activity of the RA, EO, and ES muscles was found in freeweight exercises. The greatest IO activity was observed in core stability exercises, while traditional
exercises showed the greatest MUL activation. However, a lack of research regarding TA activation
during core physical fitness exercises was revealed, in addition to a lack of consistency between the
studies when applying methods to measure EMG activity.