Neuromuscular adaptations to concurrent strength and endurance training

John P. McCarthy, Myron A. Pozniak, James C. Agre

Research output: Contribution to journalArticle

132 Scopus citations

Abstract

Purpose: The purpose of this study was to examine muscle morphological and neural activation adaptations resulting from the interaction between concurrent strength and endurance training. Methods: Thirty sedentary healthy male subjects were randomly assigned to one of three training groups that performed 10 wk of 3-d·wk-1 high-intensity strength training (S), cycle endurance training (E), or concurrent strength and endurance training (CC). Strength, quadriceps-muscle biopsies, computed tomography scans at mid-thigh, and surface electromyogram (EMG) assessments were made before and after training. Results: S and CC groups demonstrated similar increases (P < 0.0001) in both thigh extensor (12 and 14%) and flexor/adductor (7 and 6%) muscle areas. Type II myofiber areas similarly increased (P < 0.002) in both S (24%) and CC (28%) groups, whereas the increase (P < 0.004) in Type I area with S training (19%) was also similar to the nonsignificant (P = 0.041) increase with CC training (13%). Significant increases (P < 0.005) in maximal isometric knee-extension torque were accompanied by nonsignificant (P ≤ 0.07) increases in root mean squared EMG amplitude of the quadriceps musculature for both S and C groups. No changes (P > 0.38) in the EMG/torque relation across 20 to 100% maximal voluntary contractions occurred in any group. A small 3% increase (P < 0.01) in thigh extensor area was the only change in any of the above variables with E training. Conclusions: Findings indicate 3-d·wk-1 concurrent performance of both strength and endurance training does not impair adaptations in strength, muscle hypertrophy, and neural activation induced by strength training alone. Results provide a physiological basis to support several performance studies that consistently indicate 3-d·wk-1 concurrent training does not impair strength development over the short term.

Original languageEnglish (US)
Pages (from-to)511-519
Number of pages9
JournalMedicine and science in sports and exercise
Volume34
Issue number3
DOIs
StatePublished - Jan 1 2002

Keywords

  • CT scan
  • EMG
  • Hypertrophy
  • Muscle fibers
  • Resistance exercise

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