PMID- 10749820
OWN - NLM
STAT- MEDLINE
DCOM- 20000517
LR  - 20171213
IS  - 8750-7587 (Print)
IS  - 0161-7567 (Linking)
VI  - 88
IP  - 4
DP  - 2000 Apr
TI  - Carbohydrate loading failed to improve 100-km cycling performance in a 
      placebo-controlled trial.
PG  - 1284-90
AB  - We evaluated the effect of carbohydrate (CHO) loading on cycling performance that 
      was designed to be similar to the demands of competitive road racing. Seven 
      well-trained cyclists performed two 100-km time trials (TTs) on separate 
      occasions, 3 days after either a CHO-loading (9 g CHO. kg body mass(-1). day(-1)) 
      or placebo-controlled moderate-CHO diet (6 g CHO. kg body mass(-1). day(-1)). A 
      CHO breakfast (2 g CHO/kg body mass) was consumed 2 h before each TT, and a CHO 
      drink (1 g CHO. kg(.)body mass(-1). h(-1)) was consumed during the TTs to 
      optimize CHO availability. The 100-km TT was interspersed with four 4-km and five 
      1-km sprints. CHO loading significantly increased muscle glycogen concentrations 
      (572 +/- 107 vs. 485 +/- 128 mmol/kg dry wt for CHO loading and placebo, 
      respectively; P < 0.05). Total muscle glycogen utilization did not differ between 
      trials, nor did time to complete the TTs (147.5 +/- 10.0 and 149.1 +/- 11.0 min; 
      P = 0.4) or the mean power output during the TTs (259 +/- 40 and 253 +/- 40 W, P 
      = 0.4). This placebo-controlled study shows that CHO loading did not improve 
      performance of a 100-km cycling TT during which CHO was consumed. By preventing 
      any fall in blood glucose concentration, CHO ingestion during exercise may offset 
      any detrimental effects on performance of lower preexercise muscle and liver 
      glycogen concentrations. Alternatively, part of the reported benefit of CHO 
      loading on subsequent athletic performance could have resulted from a placebo 
      effect.
FAU - Burke, L M
AU  - Burke LM
AD  - Department of Sports Nutrition, Australian Institute of Sport, Belconnen, 
      Canberra, Australian Capital Territory 2616.
FAU - Hawley, J A
AU  - Hawley JA
FAU - Schabort, E J
AU  - Schabort EJ
FAU - St Clair Gibson, A
AU  - St Clair Gibson A
FAU - Mujika, I
AU  - Mujika I
FAU - Noakes, T D
AU  - Noakes TD
LA  - eng
PT  - Clinical Trial
PT  - Controlled Clinical Trial
PT  - Journal Article
PT  - Multicenter Study
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Appl Physiol (1985)
JT  - Journal of applied physiology (Bethesda, Md. : 1985)
JID - 8502536
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Liver Glycogen)
RN  - 0 (Placebos)
RN  - 9005-79-2 (Glycogen)
SB  - IM
MH  - Adult
MH  - Bicycling/*physiology
MH  - Body Weight
MH  - *Dietary Carbohydrates
MH  - Glycogen/*metabolism
MH  - Humans
MH  - Liver Glycogen/metabolism
MH  - Male
MH  - Muscle, Skeletal/*physiology
MH  - Oxygen Consumption
MH  - Placebos
EDAT- 2000/04/06 09:00
MHDA- 2000/05/20 09:00
CRDT- 2000/04/06 09:00
PHST- 2000/04/06 09:00 [pubmed]
PHST- 2000/05/20 09:00 [medline]
PHST- 2000/04/06 09:00 [entrez]
AID - 10.1152/jappl.2000.88.4.1284 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 2000 Apr;88(4):1284-90. doi: 10.1152/jappl.2000.88.4.1284.