Effects of carbohydrate supplementation on competitive runners undergoing overload training followed by a session of intermittent exercise
- 465 Downloads
This study evaluated the effects of a micro cycle of overload training (1st–8th day) on metabolic and hormonal responses in male runners with or without carbohydrate supplementation and investigated the cumulative effects of this period on a session of intermittent high-intensity running and maximum-performance-test (9th day). The participants were 24 male runners divided into two groups, receiving 61% of their energy intake as CHO (carbohydrate-group) and 54% in the control-group (CON). The testosterone was higher for the CHO than the CON group after the overload training (694.0 ± 54.6 vs. CON 610.8 ± 47.9 pmol/l). On the ninth day participants performed 10 × 800 m at mean 3 km velocity. An all-out 1000 m running was performed before and after the 10 × 800 m. Before, during, and after this protocol, the runners received solution containing CHO or the CON equivalent. The performance on 800 m series did not differ in either group between the first and last series of 800 m, but for the all-out 1000 m test the performance decrement was lower for CHO group (5.3 ± 1.0 vs. 10.6 ± 1.3%). The cortisol concentrations were lower in the CHO group in relation to CON group (22.4 ± 0.9 vs. 27.6 ± 1.4 pmol/l) and the IGF1/IGFBP3 ratio increased 12.7% in the CHO group. During recovery, blood glucose concentrations remained higher in the CHO group in comparison with the CON group. It was concluded that CHO supplementation possibly attenuated the suppression of the hypothalamic-pituitary-gonadal axis and resulted in less catabolic stress, and thus improved running performance.
KeywordsCarbohydrate supplementation Overload training Testosterone Cortisol Intermittent exercise IGF1
The authors thank FAPESP for the fellowship granted as well as Claire Neesham and Allan Jorgensen for proofreading the manuscript.
- Kraemer WJ, Fragala MS, Watson G, Volek JS, Rubin MR, French DN, Maresh CM, Vingren JL, Hatfield DL, Spiering BA, Yu-Ho J, Hughes SL, Case HS, Stuempfle KJ, Lehmann DR, Bailey S, Evans DS (2008) Hormonal responses to a 160-km race across frozen Alaska. Br J Sports Med 42:116–120CrossRefPubMedGoogle Scholar
- Simões HG, Denadai BS, Baldissera V, Hill DW, Campbell CSG (2005) Relationships and significance of lactate minimum, critical velocity, heart rate detection and 3000 m track-tests for running. J Sports Med Phys Fitness 42:441–451Google Scholar
- TACO (2006) Tabela brasileira de composição de alimentos. NEPA-UNICAMP, Version II, 2nd edn. Campinas, São Paulo, 113 pp. http://www.unicamp.br/nepa/taco/. Accessed 30 September 2009