Thesis-1987-Walker.pdf (4.32 MB)
Nutritional influences on endurance running performance in man
thesis
posted on 2012-11-26, 13:54 authored by Moya P.D. WalkerThe overall aim of this thesis was to examine the influence of
nutritional modifications of the normal diet, on endurance running
performance.
There is considerable evidence demonstrating that a high carbohydrate
(CHO) diet in the days prior to exercise can significantly increase
the endurance capacity of cycle ergometry. However, there is limited
evidence to show that endurance running performance is also enhanced
by a high CHO diet. Thus the first study presented in this thesis
examined the influence of a high CHO diet on endurance running
performance over a distance of 30km. Subjects (n=18) attempted to
complete two 30km runs on a motorised treadmill as fast as possible, 7
days apart. Prior to Run 1 all individuals consumed their prescribed
normal diet, whereas after Run 1, the normal diet was supplemented
with either high CHO confectionery products for the Carbohydrate group
(n=9), or additional fat and protein for the Control group (n=9).
There were no significant improvements in the performance time for the
individuals in the CHO group, although they achieved a 1.91
improvement compared to a 0.21 decrement in performance time for the
Control group. However, the high CHO group demonstrated significantly
higher running speeds over the last 5km (p(O.OOI), as well as
significantly higher respiratory exchange ratios and blood glucose
concentrations over the final 10km. To examine the influence of CHO ingestion dur-ing endurance exercise,
trained individuals (n=15) ran two simulated races on a motorised
treadmill, 7 days apart. The subjects aimed to cover as much distance
as possible within two hours, whilst ingesting either a CHO supplement
or a Placebo. Seven days later subjects repeated the run whilst
ingesting the fluid not ingested ,on Run I. Although there were no
significant differences in'the distances covered, the CHO run showed
significantly higher running speeds towards the end of the run
(p(0.05), with significantly higher blood glucose concentrations
during the last 30 min of exercise. Fat metabolism was noticeably
suppressed with a concomitant increase in CHO oxidation.
The final study attempted to enhance free fatty acid oxidation (FFA)
by increasing carnitine availability, the transporter of FFA into the
mitochondria. Subjects (n=14) completed two endurance capacity runs to
exhaustion at 70 IVO. max, 3 weeks apart. During the 3 week interim
period, half the individuals supplemented their diet with a carnitine
supplement, whilst the others supplemented their diet with a placebo.
There was no significant improvement in the run time to exhaustion
after carnitine supplementation. However, there were significantly
lower R values and blood glucose concentrations at exhaustion for the
carnitine group, suggesting an increase in fat metabolism with a
concurrent reduction in CHO utilisation. Thus certain nutritional
modifications of the normal diet may enhance endurance running
performance in man.
History
School
- Sport, Exercise and Health Sciences
Publisher
© Moya P.D. WalkerPublication date
1987Notes
A Master's Thesis. Submitted in partial fulfilment of the requirements for the award of Master of Philosophy of Loughborough University.Language
- en