Amino Acids

, 37:629

Changes in amino acid concentration in plasma and type I and type II fibres during resistance exercise and recovery in human subjects

Original Article


Eight male subjects performed leg press exercise, 4 × 10 repetitions at 80% of their maximum. Venous blood samples were taken before, during exercise and repeatedly during 2 h of recovery. From four subjects, biopsies were taken from the vastus lateralis muscle prior to, immediately after and following one and 2 h of recovery. Samples were freeze-dried, individual muscle fibres were dissected out and identified as type I or type II. Resistance exercise led to pronounced reductions in the glutamate concentration in both type I (32%) and type II fibres (70%). Alanine concentration was elevated 60–75% in both fibre types and 29% in plasma. Glutamine concentration remained unchanged after exercise; although 2 h later the concentrations in both types of fibres were reduced 30–35%. Two hours after exercise, the plasma levels of glutamate and six of the essential amino acids, including the branched-chain amino acids were reduced 5–30%. The data suggest that glutamate acts as an important intermediate in muscle energy metabolism during resistance exercise, especially in type II fibres.


Amino acids Muscle fibre types Resistance exercise 

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Swedish School of Sport and Health SciencesStockholmSweden
  2. 2.Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
  3. 3.Department of Clinical SciencesSwedish University of Agricultural SciencesUppsalaSweden

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