Curvilinear Dose-Response Relationship of Carbohydrate (0-120 g[middle dot]h-1) and Performance.

• Autores: JohnEric W. Smith, David D. Pascoe, Dennis H. Passe, Brent C. Ruby, Laura K. Stewart, Lindsay B. Baker, Jeffrey J. Zachwieja
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 45, Nº. 2, 2013, págs. 336-341
• Idioma: inglés
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• Dialnet Métricas: 1 Cita
• Resumen

  • AB Background: There is a lack of consensus regarding the optimal range of carbohydrate (CHO) ingestion rates recommended for endurance athletes. Purpose: This study investigated the relationship between CHO dose and cycling time trial performance to identify an optimal range of CHO ingestion rates for endurance performance. Methods: Fifty-one cyclists and triathletes (28 +/- 7 yr, mean +/- SD) across four research sites completed four trials. Each trial consisted of a 2-h constant load ride at 95% of the workload that elicited a 4-mmol[middle dot]L-1 blood lactate concentration immediately followed by a computer-simulated 20-km time trial, which subjects were asked to complete as quickly as possible. Twelve CHO electrolyte (18 mmol[middle dot]L-1 Na, 3 mmol[middle dot]L-1 K, and 11 mmol[middle dot]L-1 Cl) beverages (three at each site) were tested in a double-blind manner, providing subjects 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 g CHO (1:1:1 glucose-fructose-maltodextrin) per hour during the 2-h constant load ride at a fluid intake rate of 1 L[middle dot]h-1. All subjects also consumed a noncaloric placebo on one counterbalanced test occasion. Data were natural log transformed, subjected to a mixed-model analysis, and are reported as adjusted treatment means. Results: We estimate incremental performance improvements of 1.0%, 2.0%, 3.0%, 4.0%, and 4.7% at 9, 19, 31, 48, and 78 g[middle dot]h-1, respectively, with diminishing performance enhancement seen at CHO levels >78 g[middle dot]h-1. Conclusions: CHO beverage ingestion and endurance (~160 min) performance appear to be related in a curvilinear dose-response manner, with the best performance occurring with a CHO (1:1:1 glucose-fructose-maltodextrin) ingestion rate of 78 g[middle dot]h-1.