MRI quantification of muscle activity after volitional exercise and neuromuscular electrical stimulation

Misa Ogino, Naoto Shiba, Takashi Maeda, Kiyohiko Iwasa, Yoshihiko Tagawa, Shigeaki Matsuo, Hiroshi Nishimura, Toshiyasu Yamamoto, Kensei Nagata, Jeffrey R. Basford

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Objective: The efficacy, and even the depth, of muscle stimulation during surface electrode neuromuscular electrical stimulation (NMES) is a matter of debate. This study addresses these issues by assessing the utility of a magnetic resonance imaging (MRI) technique in localizing and quantitating changes in the nature of MRI signals in the quadriceps muscle after volitional exercise and NMES. Design: Volitional isometric and NMES-evoked quadriceps muscle activity was evaluated in two controlled trials. In the first, isometric quadriceps strength was determined during NMES and maximal volitional isometric exercise in six healthy men. In the second, changes in the ratio of MRI T2 signal intensities before and after volitional isometric exercise and NMES were used to quantitate MRI signal changes associated with muscle activation in 12 additional healthy men. Results: MRI clearly detected quadriceps muscle tissue activation after both volitional and stimulated contractions, even though the NMES knee extension torque was only 23.5% that of maximal volitional isometric exercise. In particular, the T2 intensity ratios increased 26.5% ± 17.3% (mean ± standard deviation) after volitional exercise and 12.9% ± 12.8% after NMES. This pattern of volitional isometric exercise, producing larger T2 intensity ratio values than NMES, was present in both deep and superficial layers and throughout the quadriceps muscle. Conclusions: Although volitional muscle contractions were several times stronger than those induced by NMES in this study, our findings support the idea that MRI can provide a noninvasive way to quantitate and localize volitional and electrically stimulated muscle activation.

Original languageEnglish (US)
Pages (from-to)446-451
Number of pages6
JournalAmerican Journal of Physical Medicine and Rehabilitation
Issue number6
StatePublished - 2002


  • Exercise
  • Magnetic Resonance Imaging
  • Muscle Activity
  • Neuromuscular Electrical Stimulation
  • Quadriceps Muscle

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation


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