The use of electromyography and magnetic resonance imaging to evaluate a core strengthening exercise programme

J Back Musculoskelet Rehabil. 2018;31(2):355-362. doi: 10.3233/BMR-169780.


Background: The question that was asked in the study was whether a training routine based on curl-up exercises with a load provided by body mass of the person increases local muscle strength or local muscle endurance.

Objective: The aim of this study was to evaluate the effect of 4 weeks training based on a small load and low movement velocity on electrical activity (EMG), cross-sectional area (CSA) of core stabilisers.

Methods: The EMG activity was measured in the rectus abdominis (RA), obliquus abdominis externus and erector spinae (ES) muscles. CSA of the muscles: RA, anterolateral abdominal, psoas major, quadratus lumborum, ES, and multifidus at the level of L3-L4 were measured too.

Results: The training increased the CSA and thickness in most of the muscles studied. Statistically significant correlation was found only for the ES circumference (left side) and EMG activity for the right side (r= 0.627, p= 0.022) and left side (r= 0.624, p= 0.023).

Conclusions: The training programme resulted in a increase in the number of curl-up repetitions revealing an endurance increase in abdominal muscles. Furthermore, there was a increase in the EMG activity of the RA. An increase of the CSA of all tested muscles showed an increase of muscle active force.

Keywords: Low back pain; curl-up exercise; muscle hypertrophy.

MeSH terms

  • Abdominal Muscles / physiology
  • Adult
  • Back Muscles / physiology
  • Electromyography*
  • Exercise / physiology
  • Exercise Therapy / methods
  • Female
  • Healthy Volunteers
  • Humans
  • Magnetic Resonance Imaging*
  • Movement / physiology
  • Muscle Strength*
  • Muscle, Skeletal / diagnostic imaging
  • Muscle, Skeletal / physiology*
  • Physical Endurance
  • Psoas Muscles / physiology
  • Rectus Abdominis / physiology
  • Resistance Training*
  • Young Adult