Acute effects of passive stretching of the plantarflexor muscles on neuromuscular function: The influence of age

Eric D. Ryan, Trent J. Herda, Pablo B. Costa, Ashley A. Herda, Joel T. Cramer

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


The acute effects of stretching on peak force (Fpeak), percent voluntary activation (%VA), electromyographic (EMG) amplitude, maximum range of motion (MROM), peak passive torque, the passive resistance to stretch, and the percentage of ROM at EMG onset (%EMGonset) were examined in 18 young and 19 old men. Participants performed a MROM assessment and a maximal voluntary contraction of the plantarflexors before and immediately after 20 min of passive stretching. Fpeak (-11%),%VA (-6%), and MG EMG amplitude (-9%) decreased after stretching in the young, but not the old (P>0.05). Changes in Fpeak were related to reductions in all muscle activation variables (r=0.56-0.75), but unrelated to changes in the passive resistance to stretch (P≥0.24). Both groups experienced increases in MROM and peak passive torque and decreases in the passive resistance to stretch. However, the old men experienced greater changes in MROM (P<0.001) and passive resistance ( P=0.02-0.06). Changes in MROM were correlated to increases in peak passive torque (r=0.717), and the old men also experienced a nonsignificant greater (P=0.08) increase in peak passive torque. %EMGonset did not change from pre- to post-stretching for both groups (P=0.213), but occurred earlier in the old (P=0.06). The stretching-induced impairments in strength and activation in the young but not the old men may suggest that the neural impairments following stretching are gamma-loop-mediated. In addition, the augmented changes in MROM and passive torque and the lack of change in %EMGonset for the old men may be a result of age-related changes in muscle-tendon behavior.

Original languageEnglish (US)
Article number9672
Issue number4
StatePublished - Aug 2014
Externally publishedYes


  • Muscle activation
  • Passive torque
  • Range ofmotion
  • Stretch tolerance
  • Stretching-induced force deficit

ASJC Scopus subject areas

  • Aging
  • Geriatrics and Gerontology


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