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Nordin, Marie
Publications (1 of 1) Show all publications
Borgenvik, M., Nordin, M., Mattsson, C. M., Enqvist, J. K., Blomstrand, E. & Ekblom, B. (2012). Alterations in amino acid concentrations in the plasma and muscle in human subjects during 24 h of simulated adventure racing. European Journal of Applied Physiology, 112, 3679-3688
Open this publication in new window or tab >>Alterations in amino acid concentrations in the plasma and muscle in human subjects during 24 h of simulated adventure racing
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2012 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 112, p. 3679-3688Article in journal (Refereed) Published
Abstract [en]

This investigation was designed to evaluate changes in plasma and muscle levels of free amino acids during an ultra-endurance exercise and following recovery. Nine male ultra-endurance trained athletes participated in a 24-h standardized endurance trial with controlled energy intake. The participants performed 12 sessions of running, kayaking and cycling (4 x each discipline). Blood samples were collected before, during and after exercise, as well as after 28 h of recovery. Muscle biopsies were taken 1 week before the test and after exercise, as well as after 28 h of recovery. During the 24-h exercise, plasma levels of branched-chain (BCAA), essential amino acids (EAA) and glutamine fell 13%, 14% and 19% (P<0.05) respectively, whereas their concentrations in muscle were unaltered. Simultaneously, tyrosine and phenylalanine levels rose 38% and 50% (P<0.05) in the plasma and 66% and 46% (P<0.05) in muscle, respectively. After the 24-h exercise, plasma levels of BCAA were positively correlated with muscle levels of glycogen (r2=0.73, P<0.05), as was the combined concentrations of muscle tyrosine and phenylalanine with plasma creatine kinase (r2=0.55, P<0.05). Following 28-h of recovery, plasma and muscle levels of amino acids had either returned to their initial levels or were elevated. In conclusion, ultra-endurance exercise caused significant changes elevations in plasma and muscle levels of tyrosine and phenylalanine, which suggest an increase in net muscle protein breakdown during exercise. There was a reduction in plasma concentrations of EAA and glutamine during exercise, whereas no changes were detected in their muscle concentration after exercise.

Keywords
Adventure racing, branched-chained amino acids, creatine kinase, phenylalanine, skeletal muscle, tyrosine
National Category
Physiology Nutrition and Dietetics Sport and Fitness Sciences
Research subject
Medicine/Technology
Identifiers
urn:nbn:se:gih:diva-1742 (URN)10.1007/s00421-012-2350-8 (DOI)
Projects
Physiology of Adventure Racing
Available from: 2011-02-07 Created: 2011-02-07 Last updated: 2018-01-12Bibliographically approved
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