title: Improvement of 2000-m rowing performance with caffeinated carbohydrate-gel ingestion.
abstract: OBJECTIVE
  To investigate the effect of ingesting a caffeinated carbohydrate gel (CC) 10 minutes prior on 2000-m rowing performance compared with a carbohydrate-only placebo gel (CP).
  
  
  METHODS
  A counterbalanced, single-blind, crossover study design was employed (N=13). All participants completed 1 familiarization trial followed by 2 experimental rowing time trials. The experimental trials were performed 10 min after ingesting CP (21.6 g of carbohydrate, 0 mg caffeine) or CC (21.6 g carbohydrate, 100 mg caffeine), and heart rate (HR), oxygen consumption (VO2), carbon dioxide production, minute ventilation (VE), respiratory-exchange ratio (RER), rating of perceived exertion (RPE), gastrointestinal discomfort (GI), and thirst perception (Thirst) were recorded every 200 m. Blood lactate [La-] was recorded immediately before and after exercise.
  
  
  RESULTS
  A pairedsamples t test identified a significant improvement in 2000-m performance of 5.2±3.9 s (1.1%±1.7%; P=.034). Two-way repeated-measures ANOVA revealed no significant treatment effect for HR (177±8 vs 177±9 beats/min, P=.817), VO2 (46.1±6.5 vs 46.6±6.2 mL·kg(-1)·min(-1), P=.590), VE (121.8±14.7 vs 124.8±15.7 L/min, P=.490), RPE, GI, or Thirst for CP and CC, respectively. Paired-samples t tests revealed no treatment effect for postexercise [La-] between CP and CC (11.72±2.69 vs 12.26±3.13 mmol/L, P=.534).
  
  
  CONCLUSIONS
  A relatively low dose of caffeine (1.3±0.1 mg/kg body mass) in an isotonic carbohydrate gel ingested only 10 min before performance improved 2000-m rowing time by 5.2±7.8 s (1.1%±1.7%).
authors.affiliation: Dept of Sport and Exercise Science, University of Portsmouth, Portsmouth, UK.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Scott
authors.forename: Thomas
authors.initials: T
authors.lastname: O'Leary
authors.forename: Simon
authors.initials: S
authors.lastname: Walker
authors.forename: Rachel
authors.initials: R
authors.lastname: Owen
mesh_terms: D000284:Administration, Oral; D054874:Athletic Performance / Q000502:physiology*; D002110:Caffeine / Q000008:administration & dosage*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D005080:Exercise Test; D005782:Gels; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000187:drug effects*; D012420:Running / Q000502:physiology*; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D004040:Dietary Carbohydrates; D004338:Drug Combinations; D005782:Gels; D002110:Caffeine