title: High versus low glycemic index 3-h recovery diets following glycogen-depleting exercise has no effect on subsequent 5-km cycling time trial performance.
abstract: OBJECTIVE
  Some athletes train/compete multiple times in a single day and rapid restoration of muscle and hepatic glycogen stores is therefore important for athletic performance.
  
  
  METHODS
  Randomised, counterbalanced, crossover, single blinded study investigated the effects of low/high glycaemic index (GI) meals on the physiological responses to a 3-h recovery period and subsequent 5-km cycling time trial (TT).
  
  
  METHODS
  Seven male cyclists completed glycogen-depleting exercise followed by a 3-h recovery period, when participants consumed either a high or low GI meal providing 2gkg(-1) BM of carbohydrate. Participants then performed a 5-km cycling TT. Blood samples were analysed for glucose insulin, free fatty acid (FFA) and triglyceride.
  
  
  RESULTS
  There was no significant difference between the median (IQR) cycling TT time of 8.5 (3.0) min in the LGI condition and 8.4 (1.8) min in the HGI condition (p=0.45). Serum insulin was significantly higher in the HGI condition throughout the 3-h recovery period (p=0.025), FFA concentrations were higher in the HGI condition only at 30min into recovery (p=0.008). The respiratory exchange ratio (p=0.028) and carbohydrate oxidation rate (p=0.015) increased over time in the HGI condition, whereas the rate of fat oxidation demonstrated the opposite response (p=0.001). No significant differences between conditions were observed for any physiological variables at the end of the 5-km TT.
  
  
  CONCLUSIONS
  Although the GI of the two meals indicated important metabolic differences during the recovery period, there was no evidence suggesting these differences influenced subsequent 5-km TT performance.
authors.affiliation: University of Hull, United Kingdom.
authors.forename: Laura J S
authors.initials: LJ
authors.lastname: Brown
authors.forename: Adrian W
authors.initials: AW
authors.lastname: Midgley
authors.forename: Rebecca V
authors.initials: RV
authors.lastname: Vince
authors.forename: Leigh A
authors.initials: LA
authors.lastname: Madden
authors.forename: Lars R
authors.initials: LR
authors.lastname: McNaughton
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D038321:Glycemic Index; D006801:Humans; D008297:Male; D020127:Recovery of Function; D055815:Young Adult