Chapter 47, Problem 5Q

Summary Introduction

To review:

To suggest a strategy for the improvement of one’s performance in a long-distance marathon.

Given:

In the given study, trained cyclists were asked to perform strenuous exercises until fatigued (Table 1). Each of them was given placebo in the interval of 20 minutes. The next day, each of them was given glucose water, after every 20 minutes. The time to fatigue, the muscle glycogen levels, the blood free-fatty acid levels, and the carbohydrate oxidation rate in the blood were measured.

Table 1: Study performed on trained cyclists about strenuous exercises.

Treatment	At 0 hours, the muscle glycogen levels	At the end of 2 hours, the muscle glycogen levels	At the end of 3 hours, the muscle glycogen levels	At the end of 4 hours, the muscle glycogen levels	The time to fatigue
Placebo (flavored water)	163±13	60±9	37±5	No data	3.02±0.19
Glucose solution	173±11	71±11	44±12	39±8	0.33

Introduction:

When an athlete is training for endurance exercise, they undergo repeated muscle contractions. There is a limit on how long the exercise can be carried on, depending on the time it takes for the muscles to get fatigued. One important factor that leads to the sustainability of muscles activity in such long duration exercises is the kind of metabolic fuel which is consumed during the time period of the exercise.