Effects of motor imagery combined with action observation training on the lateral specificity of muscle strength in healthy subjects

Biomed Res. 2019;40(3):107-113. doi: 10.2220/biomedres.40.107.


Unilateral training of both lateral limbs increases unilateral muscle strength, whereas bilateral training increases bilateral muscle strength, a phenomenon known as lateral specificity in resistance training. Although motor imagery (MI) combined with action observation (AO) (i.e., MI + AO) training increases muscle strength, it is not completely understood whether such training increases the lateral specificity of muscle strength in a way resistance training does. To investigate whether MI + AO induces lateral specificity of muscle strength increase, 18 healthy subjects were divided into groups: MI + AO and the control groups. The control group watched a movie of natural sceneries for ten minutes per day five times a week for three weeks, whereas the MI + AO group imagined bilateral shoulder flexion while watching a movie of athletes performing bilateral shoulder flexion with barbells or dumbbells, with the same time schedule. The MI + AO group alone showed a significant increase in bilateral shoulder strength at three weeks after the intervention compared with the baseline. Unilateral shoulder strength was not significantly altered. These results suggest that MI + AO training increases muscle strength, providing evidence that similar to resistance training, lateral specificity also exists in MI + AO training.

MeSH terms

  • Adult
  • Electromyography
  • Exercise
  • Female
  • Healthy Volunteers
  • Humans
  • Male
  • Motor Activity*
  • Muscle Strength*
  • Muscle, Skeletal / physiology*
  • Young Adult