Multiple-Transportable Carbohydrate Effect on Long-Distance Triathlon Performance

The ingestion of multiple (2:1 glucose–fructose) transportable carbohydrate in beverages at high rates (>78 g·h−1) during endurance exercise enhances exogenous carbohydrate oxidation, fluid absorption, gut comfort, and performance relative to glucose alone. However, during long-distance endurance competition, athletes prefer a solid–gel–drink format, and the effect size of multiple-transportable carbohydrate is unknown. Purpose: This study aimed to determine the effect of multiple-transportable carbohydrate on triathlon competition performance when ingested within bars, gels, and drinks. Methods: A double-blind randomized controlled trial was conducted within two national-body sanctioned half-ironman triathlon races held 3 wk apart in 74 well-trained male triathletes (18–60 yr; >2 yr competition experience). Carbohydrate comprising glucose/maltodextrin–fructose (2:1 ratio) or standard isocaloric carbohydrate (glucose/maltodextrin only) was ingested before (94 g) and during the cycle (2.5 g·km−1) and run (7.8 g·km−1) sections, averaging 78.6 ± 6.6 g·h−1, partitioned to bars (25%), gels (35%), and drink (40%). Postrace, 0- to 10-unit Likert-type scales were completed to assess gut comfort and energy. Results: The trial returned low dropout rate (9%), high compliance, and sensitivity (typical error 2.2%). The effect of multiple-transportable carbohydrate on performance time was −0.53% (95% confidence interval = −1.30% to 0.24%; small benefit threshold = −0.54%), with likelihood-based risk analysis supporting adoption (benefit–harm ratio = 48.9%:0.3%; odds ratio = 285:1). Covariate adjustments for preexercise body weight and heat stress had negligible impact performance. Multiple-transportable carbohydrate possibly lowered nausea during the swim and bike; otherwise, effects on gut comfort and perceived energy were negligible. Conclusions: Multiple-transportable (2:1 maltodextrin/glucose–fructose) compared with single-transportable carbohydrate ingested in differing format provided a small benefit to long-distance triathlon performance, inferred as adoption worthy. Large sample in-competition randomized trials offer ecological validity, high participant throughput, compliance, and sensitivity for evaluation of health and performance interventions in athletes.

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