Muscle activation is different when the same muscle acts as an agonist or an antagonist during voluntary movement

Mark B. Shapiro*, Janey Prodoehl, Daniel M. Corcos, Gerald L. Gottlieb

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


During movement, the intrinsic muscle force-velocity property decreases the net force for the shortening muscle (agonist) and increases it for the lengthening muscle (antagonist). The authors present a quantitative analysis of the effect ofthat muscle property on activation and force output of the same muscle acting as agonist and antagonist in fast and medium speed goal-oriented movements. They compared biceps activation and force output when that muscle was the agonist in a series of elbow flexions and when it was the antagonist in a series of elbow extensions. They performed the same analysis for the lateral, long, and medial heads of the triceps muscle. Muscle EMG was about 2 times larger and the angular impulse developed by the modeled contractile torque was up to 3 times larger when the muscle or muscles acted as the agonist than when the same muscle or muscles acted as the antagonist in movements with similar kinematics. The large effect of the muscle force-velocity property strongly suggests that the neural controller must account for intrinsic muscle properties to generate movements with a commonly observed bell-shaped velocity profile.

Original languageEnglish (US)
Pages (from-to)135-145
Number of pages11
JournalJournal of motor behavior
Issue number2
StatePublished - Mar 2005


  • Electromyogram (EMG)
  • Human
  • Model
  • Motor control
  • Movement
  • Muscle

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience

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