title: Effects of a daily mixed nutritional supplement on physical performance, body composition, and circulating anabolic hormones during 8 weeks of arduous military training.
abstract: The aim of this work was to investigate the effect of a daily mixed nutritional supplement upon body composition, physical performance, and circulating anabolic hormones in soldiers undergoing arduous training. Thirty males received either a habitual diet alone (CON, n = 15) or with the addition of a daily mixed supplement (SUP, n = 15) of ∼5.1 MJ·d⁻¹ during 8 weeks of training. Body composition (DEXA), maximal dynamic lift strength (MDLS), and vertical jump (VJ) were assessed, and resting blood samples were collected before and after training. Blood analysis included insulin-like growth factors (IGF-1, IGF BP-1, and IGF BP-3), testosterone, and cortisol. There were no group differences at baseline. Body mass loss (mean ± SD) (CON 5.0 ± 2.3, SUP 1.6 ± 1.5 kg), lean mass loss (CON 2.0 ± 1.5, SUP 0.7 ± 1.5 kg), and fat mass loss (CON 3.0 ± 1.6, SUP 0.9 ± 1.8 kg) were significantly blunted by SUP. CON experienced significant decrements in MDLS (14%), VJ (10%), and explosive leg power (11%) that were prevented by SUP. Military training significantly reduced circulating IGF-1 (28%), testosterone (19%), and the testosterone:cortisol ratio (24%) with no effect of SUP. Circulating IGF BP-1 concentration and cortisol remained unchanged throughout, although SUP abolished the significant decrease in circulating IGF BP-3 (20%) on CON. In conclusion, a daily mixed nutritional supplement attenuated decreases in body mass and lean mass and prevented the decrease in physical performance during an arduous military training program.
authors: Extremes Research Group, Bangor University, Bangor, Gwynedd LL57 2PZ, UK.
authors: Matthew B
authors: MB
authors: Fortes
authors: Bethany C
authors: BC
authors: Diment
authors: Julie P
authors: JP
authors: Greeves
authors: Anna
authors: A
authors: Casey
authors: Rachel
authors: R
authors: Izard
authors: Neil P
authors: NP
authors: Walsh
mesh_terms: D000328:Adult; D054874:Athletic Performance; D015415:Biomarkers / Q000097:blood; D001823:Body Composition; D019587:Dietary Supplements; D015444:Exercise; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D008889:Military Personnel; D058573:Performance-Enhancing Substances / Q000008:administration & dosage*; D010807:Physical Endurance; D013739:Testosterone / Q000097:blood*; D014142:Track and Field; D006113:United Kingdom; D014891:Weight Lifting; D055815:Young Adult
chemical_list: D015415:Biomarkers; C032231:IGFBP1 protein, human; C515497:IGFBP3 protein, human; D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D058573:Performance-Enhancing Substances; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D006854:Hydrocortisone