NUTRITION IN SPORT

(Martin Jones) #1

10 After drinking a lot, the stomach may feel
empty and uncomfortable. In this case it may be
wise to eat some light digestible solid food
(CHO). During long, low-intensity races, solid
food can be eaten also in the first phase of the
race.
11 Factors such as fibre content, protein content,
high osmolality and high CHO concentrations
have been associated with the development of
gastrointestinal symptoms during exercise, and
thus should be avoided during exercise.


Nutrition after exercise

Quick recovery is an extremely important aspect
of training and frequent competitions. Especially
during repeated days of training or in stage
races, it is important to recover as quickly as pos-
sible. Dietary measures have been shown to
influence recovery significantly. The restoration
of muscle glycogen stores and fluid balance after
heavy training or competition is probably the
most important factor determining the time
needed to recover. The rate at which glycogen
can be formed (synthesized) is dependent on
several factors:
1 The quantitative CHO ingestion.


570 sport-specific nutrition


2 The type of CHO.
3 The timing of CHO ingestion after exercise.
4 Coingestion of other nutrients.

Amount of CHO ingestion
The quantity of CHO is by far the most important
factor determining the rate of glycogen resynthe-
sis. In studies, it appeared that the muscle glyco-
gen resynthesis rate of 50 g CHO ingested every
2 h was double that of 25 g CHO ingested every
2 h (Blomet al.1987; Ivyet al.1988b). When more
than 50 g was ingested (100–225 g), muscle glyco-
gen storage did not further increase (Blomet al.
1987; Ivyet al.1988b). Thus, 50 g in 2 h (or
25 g · h–1) appears to result in a maximum rate
of postexercise muscle glycogen resynthesis.
Frequent small meals do not appear to have an
advantage over a few large meals.

Type of CHO
To optimally restore glycogen levels after exer-
cise, a source of CHO which is easily digested
and absorbed is needed. The rate of absorption
of a certain CHO is reflected by the glycaemic
index. Foods with a moderate to high glycaemic

Fig. 43.5Rehydration and
carbohydrate loading start
immediately after the race. Photo
© Cor Vos.
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