creatine. In addition, very little is known about
any possible side-effect of a frequent intake of
creatine. Regular high concentrations of creatine
in the blood may, on a long-term basis, have
negative effects on the kidney, which is the organ
that has to eliminate the excess creatine. One
should also consider that ingestion of creatine
can be considered as doping, even though it is
not on the IOC doping list. It may be argued that
creatine is a natural compound and that it is con-
tained in the food. However, it is almost impossi-
ble to get doses of creatine corresponding to
those used in the experiments which showed
enhanced performance, as the content of creatine
in 1 kg of raw meat is around 5 g.
Pretraining and precompetition meal
On the day of a match, the intake of fat and
protein (especially derived from meat) should be
restricted. The pretraining or prematch meal
should be ingested 3–4 h prior to competition
or training. If too much food is ingested after
this time, there still may be undigested food in
the stomach and intestine when the training or
match begins. The meal should mainly consist of
a sufficient amount of carbohydrate. It has been
demonstrated that ingestion of 312 g of carbohy-
drate 4 h prior to strenuous continuous exercise
resulted in a 15% improvement in exercise per-
formance, but no improvement was observed
when either 45 or 156 g of carbohydrate was
ingested (Sherman et al. 1989). A snack high in
carbohydrate, e.g. bread with jam, may be eaten
about 1.5 h before the match. However, these
time references are only guidelines. There are
great individual differences in the ability to
digest food. It is a good idea for players to experi-
ment with a variety of different foods at different
times before training sessions.
An improvement in exercise performance
has been observed if carbohydrate was ingested
immediately before exercise (Neufer et al. 1987).
On the other hand, glucose ingestion 30–60 min
prior to severe exercise has been shown to
produce a rapid fall in blood glucose with the
onset of exercise, an increase in muscle glycogen
utilization and a reduction in exercise time to
exhaustion (Costill et al. 1977). However, not
all studies have shown a detrimental effect of
ingesting carbohydrate before exercise, and
some studies have shown improved perfor-
mance after carbohydrate ingestion in the last
hour prior to strenuous exercise (Gleeson et al.
1986). The differences seem to be closely related
to the glucose and insulin responses. When exer-
cising with a high insulin concentration, there is
an abnormally large loss of glucose from the
blood, resulting in a low blood glucose concen-
tration. Consequently, the muscles and the brain
gradually become starved of glucose, which
eventually leads to fatigue.Food intake after exercise
Physical activity is a powerful stimulus to glyco-
gen resynthesis, as was elegantly shown in a
study where a glycogen-depleted leg attained
muscle glycogen levels twice as high as the
resting control leg during a 3-day period
(Bergström & Hultman 1966). In addition, it
seems that the muscles are particularly sensitive
to glucose uptake and glycogen resynthesis in
the period immediately after exercise (Ploug et al.
1987). It was found that the rate of glycogen
resynthesis during the first 2 h after carbohydrate
intake was faster if carbohydrate was ingested
immediately following an exercise bout, rather
than delaying the intake by 2 h (Ivy et al. 1988).
Thus, to secure a rapid resynthesis of glycogen,
an athlete should take in carbohydrates immedi-
ately after training and a match. For specific
recommendations about amount and type of car-
bohydrate, see Chapter 7.
An inverse relationship between the rate of
glycogen rebuilding and the muscle-glycogen
concentration after prolonged continuous exer-
cise or soccer match-play has been demonstrated
(Piehlet al. 1974; Jacobs et al. 1982). Therefore, in
team sports the players should be able to replen-
ish the muscle glycogen stores within 24 h after
a match, irrespective of the magnitude of the
decrease of carbohydrates during the game.
However, other factors have been shown to influ-