Mechanomyographic and electromyographic responses of the superficial muscles of the quadriceps femoris during maximal, concentric isokinetic muscle actions

Joel T. Cramer, Terry J. Housh, Glen O. Johnson, Kyle T. Ebersole, Sharon R. Perry, Anthony J. Bull

Research output: Contribution to journalArticle

24 Scopus citations


Eleven adult males (mean ± SD age = 22 ± 3 years) performed maximal, concentric isokinetic leg extension muscle actions at velocities of 60, 120, 180, 240, and 300°·s-1 on a Cybex 6000 dynamometer. The results indicated that peak torque (PT) decreased (p < 0.05) as muscle action velocity increased. Mechanomyographic (MMG) amplitude increased with velocity to 180°·s(-l) for each muscle tested (vastus lateralis = VL, rectus femoris = RF, and vastus medialis = VM). For the VL, MMG amplitude continued to increase to 240°·s(-l) and then plateaued, while the RF plateaued from 180 to 300°·s-1. The VM showed a constant increase in MMG amplitude to 300°·s-1. Electromyographic (EMG) amplitude increased to 180°·s-1 and then plateaued for each muscle. These findings indicated muscle-specific differences in MMG amplitude patterns across velocity that may be attributable to differences in fiber type composition, muscle architecture, and/or tissue layer composition. Furthermore, these results suggested that there were muscle-specific, velocity-related differences in the association between motor unit activation (EMG) and the mechanical aspects of muscular activity (MMG).

Original languageEnglish (US)
Pages (from-to)109-117
Number of pages9
JournalIsokinetics and Exercise Science
Issue number2
Publication statusPublished - Jan 1 2000


ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this