The effect of a high carbohydrate diet on running performance during a 30-km treadmill time trial.
The purpose of the present study was to examine the influence of a high carbohydrate diet on running performances during a 30-km treadmill time trial. Eighteen runners (12 men and 6 women) took part in this study and completed a 30-km time trial on a level treadmill without modifying their food intake (trial 1). The runners were then randomly assigned to a control or a carbohydrate (CHO) group. The CHO group supplemented their normal diets with additional carbohydrate in the form of confectionery products during the 7 days before trial 2; the control group matched the increased energy intake of the CHO group by consuming additional fat and protein. The mean (SEM) carbohydrate intake of both groups was 334 (22) g before trial 1, after which the CHO group consumed 566 (29) g.day-1 for the first 3 days and 452 (26) g.day-1 for the remaining 4 days of recovery. Although there was no overall difference between the performance times for the two groups during trial 2, the CHO group ran faster during the last 5 km of trial 2 than during trial 1 [3.64 (0.24) m.s-1 vs 3.44 (0.26) m.s-1; P less than 0.05]. Furthermore, the 6 men in the CHO group ran the 30 km faster after carbohydrate loading [131.0 (5.4) min vs 127.4 (4.9) min; P less than 0.05], whereas there was no such improvement in times of the men in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)
Williams
C
C
Department of Physical Education, Loughborough University, UK.
Brewer
J
J
Walker
M
M
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D005080:Exercise Test; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010807:Physical Endurance; D012420:Running
D001786:Blood Glucose; D002395:Catecholamines; D004040:Dietary Carbohydrates; D005227:Fatty Acids