Progressive resistance exercise restores some properties of the triphasic EMG pattern and improves bradykinesia: The PRET-PD randomized clinical trial

Fabian J. David*, Julie A. Robichaud, David E. Vaillancourt, Cynthia Poon, Wendy M. Kohrt, Cynthia L. Comella, Daniel M. Corcos

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


In Parkinson’s disease (PD), the characteristic triphasic agonist and antagonist muscle activation pattern during ballistic movement is impaired: the number of agonist muscle bursts is increased, and the amplitudes of the agonist and antagonist bursts are reduced. The breakdown of the triphasic electromyographic (EMG) pattern has been hypothesized to underlie bradykinesia in PD. Progressive resistance exercise has been shown to improve clinical measures of bradykinesia, but it is not clear whether the benefits for bradykinesia are accompanied by changes in agonist and antagonist muscle activity. This study examined the spatiotemporal changes in agonist and antagonist muscle activity following 24 mo of progressive resistance exercise and the combined relationship between spatiotemporal muscle activity and strength measures and upper limb bradykinesia. We compared the effects of progressive resistance exercise training (PRET) with a nonprogressive exercise intervention, modified Fitness Counts (mFC), in patients with PD. We randomized 48 participants with mild-to-moderate PD to mFC or PRET. At the study endpoint of 24 mo, participants randomized to PRET compared with mFC had significantly faster movement velocity, accompanied by significant increases in the duration, magnitude, and magnitude normalized to duration of the 1st agonist burst and fewer number of agonist bursts before peak velocity. The antagonist muscle activity was increased relative to baseline but did not differ between groups. Spatiotemporal EMG muscle activity and muscle strength were significantly associated with upper limb bradykinesia. These findings demonstrate that progressive resistance exercise improves upper limb movement velocity and restores some aspects of the triphasic EMG pattern.

Original languageEnglish (US)
Pages (from-to)2298-2311
Number of pages14
JournalJournal of neurophysiology
Issue number5
StatePublished - Nov 2016


  • Bradykinesia
  • Emg triphasic muscle activation pattern
  • PRET-PD randomized clinical trial
  • Parkinson’s disease
  • Progressive resistance exercise

ASJC Scopus subject areas

  • Physiology
  • General Neuroscience


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