Nutrients 2012, 4(12), 2035-2046; doi:10.3390/nu4122035
Differential Effects of Military Training on Fat-Free Mass and Plasma Amino Acid Adaptations in Men and Women
1
Military Nutrition Division, United States Army Research Institute of Environmental Medicine, 15 Kansas Street, Natick, MA 01760, USA
2
Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
3
Experimentation and Analysis Element, Directorate of Basic Combat Training, Fort Jackson, SC 29207, USA
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These authors contributed equally to this work.
*
Author to whom correspondence should be addressed.
Received: 2 October 2012 / Revised: 30 November 2012 / Accepted: 13 December 2012 / Published: 18 December 2012
(This article belongs to the Special Issue Interaction of Amino Acids and Dietary Proteins and Exercise on Muscle Health)
Abstract
Fat-free mass (FFM) adaptations to physical training may differ between sexes based on disparities in fitness level, dietary intake, and levels of plasma amino acids (AA). This investigation aimed to determine FFM and plasma AA responses to military training, examine whether adaptations differ between male and female recruits, and explore potential associations between FFM and AA responses to training. Body composition and plasma AA levels were assessed in US Army recruits (n = 209, 118 males, 91 females) before (baseline) and every three weeks during basic combat training (BCT), a 10-week military training course. Body weight decreased in men but remained stable in women during BCT (sex-by-time interaction, P < 0.05). Fifty-eight percent of recruits gained FFM during BCT, with more (P < 0.05) females (88%) gaining FFM than males (36%). Total plasma AA increased (P < 0.05) during BCT, with greater (P < 0.05) increases observed in females (17%) then in males (4%). Essential amino acids (EAA) and branched-chain amino acids (BCAA) were increased (P < 0.05) in females but did not change in males (sex-by-time interaction, P < 0.05). Independent of sex, changes in EAA (r = 0.34) and BCAA (r = 0.27) from baseline were associated with changes in FFM (P < 0.05); greater (P < 0.05) increases in AA concentrations were observed for those who gained FFM. Increases in FFM and plasma AA suggest that BCT elicits a more pronounced anabolic response in women compared to men, which may reflect sex-specific differences in the relative intensity of the combined training and physiological stimulus associated with BCT. View Full-TextKeywords:
skeletal muscle; essential amino acids; branched-chain amino acids; exercise training; military training; adaptation
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).
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MDPI and ACS Style
Margolis, L.M.; Pasiakos, S.M.; Karl, J.P.; Rood, J.C.; Cable, S.J.; Williams, K.W.; Young, A.J.; McClung, J.P. Differential Effects of Military Training on Fat-Free Mass and Plasma Amino Acid Adaptations in Men and Women. Nutrients 2012, 4, 2035-2046.
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