title: Multiple-Transportable Carbohydrate Effect on Long-Distance Triathlon Performance.
abstract: The ingestion of multiple (2:1 glucose-fructose) transportable carbohydrate in beverages at high rates (>78 g·h) 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.
  
  
  
  This study aimed to determine the effect of multiple-transportable carbohydrate on triathlon competition performance when ingested within bars, gels, and drinks.
  
  
  
  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) and run (7.8 g·km) sections, averaging 78.6 ± 6.6 g·h, 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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: School of Sport and Exercise, Massey University Wellington, Wellington, NEW ZEALAND.
authors.forename: David S
authors.initials: DS
authors.lastname: Rowlands
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Houltham
mesh_terms: D000293:Adolescent; D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001835:Body Weight; D003163:Competitive Behavior / Q000502:physiology; D018592:Cross-Over Studies; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004311:Double-Blind Method; D061215:Energy Drinks; D005502:Food; D005632:Fructose / Q000008:administration & dosage; D005767:Gastrointestinal Diseases / Q000517:prevention & control; D005947:Glucose / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D011134:Polysaccharides / Q000008:administration & dosage; D012420:Running / Q000502:physiology*; D013550:Swimming / Q000502:physiology*; D013696:Temperature; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates; D011134:Polysaccharides; D005632:Fructose; C008315:maltodextrin; D005947:Glucose