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Revista Brasileira de Medicina do Esporte
Print version ISSN 1517-8692
On-line version ISSN 1806-9940
AOKI, Marcelo Saldanha et al. Carbohydrate supplementation fails to revert the deleterious effects of endurance exercise upon subsequent strength performance. Rev Bras Med Esporte [online]. 2003, vol.9, n.5, pp.282-287. ISSN 1517-8692. http://dx.doi.org/10.1590/S1517-86922003000500004.
Previous studies indicated that endurance exercise might have an adverse effect on subsequent strength performance. The decrease in strength performance might be related to the changes promoted by endurance exercise in energy metabolism. Authors' aim was verify if carbohydrate (CHO) feeding can attenuate the effects of endurance exercise on strength development. To verify that hypothesis, six female university students (164 ± 5.9 cm; 64.9 ± 7.2 kg) with strength training experience were submitted to a VO2peak test (44 ± 4.3 ml.min-1) and an 1-RM test in the leg press (186 ± 22.5 kg) followed by a maximum repetitions test (2 sets of leg press exercise performed at 70% of 1-RM value until exhaustion, 1st set 21 ± 2.6 reps and 2nd set 11 ± 1.9 reps) in different days. In a double-blind design, the subjects were submitted to two different trials, receiving placebo (P) or CHO beverages (1 L of P or 6% maltodextrin solutions), 60 min before (500 ml) and during (500 ml) endurance exercise bout. These bouts were performed in a treadmill at 70% of VO2peak for 45 minutes. Subsequently, the subjects performed an 1-RM test followed by a maximum repetitions test. No changes were observed in 1-RM test. There was a similar decline in maximum repetitions test (an index of muscular endurance) in both trials (P - 1st set 13 ± 2.9 reps and 2nd set 6 ± 2.1 reps; CHO - 1st set 15 ± 2.5 reps and 2nd set 7 ± 1.7 reps, p < 0.05). Previous endurance exercise bout promoted deleterious effect upon muscular endurance task (maximum repetitions test - 70%-1-RM). CHO supplementation was inefficient to revert the effect of endurance exercise upon maximum repetitions test.
Keywords : Endurance exercise; Strength exercise; Carbohydrate; Supplementation.