Prior heavy exercise increases oxygen cost during moderate exercise without associated change in surface EMG

Joaquin U. Gonzales, Barry W. Scheuermann

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

The aim of this study was to test the hypothesis that prior heavy exercise results in a higher oxygen cost during a subsequent bout of moderate exercise due to changes in muscle activity. Eight male subjects (25 ± 2 yr, ±SE) performed moderate-moderate and moderate-heavy-moderate transitions in work rate (cycling intensity, moderate = 90% LT, heavy = 80% VO2 peak). The second bout of moderate exercise was performed after 6 min (C) or 30 s (D) of recovery. Pulmonary gas exchange was measured breath-by-breath and surface electromyography was obtained from the vastus lateralis and medialis muscles. Root mean square (RMS) and median power frequency (MdPF) were computed. Prior heavy exercise increased Δ over(V, ̇) O2 / Δ WR (C: +2.0 ± 0.8 ml min-1 W-1, D: +3.4 ± 0.8 ml min-1 W-1; P < 0.05) and decreased exercise efficiency (C: -13.3 ± 5.6%, D: -22.2 ± 4.9%; P < 0.05) during the second bout of moderate exercise in the absence of changes in RMS. MdPF was slightly elevated (∼2%) during the second bout of moderate exercise, but MdPF was not correlated with over(V, ̇) O2 (r = 0.17). These findings suggest that the increased oxygen cost during moderate exercise following heavy exercise is not due to increased muscle activity as assessed by surface electromyography.

Original languageEnglish
Pages (from-to)99-107
Number of pages9
JournalJournal of Electromyography and Kinesiology
Volume18
Issue number1
DOIs
StatePublished - Feb 2008

Keywords

  • Constant work rate exercise
  • Electromyography
  • Oxygen cost
  • Prior heavy exercise

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