There is 160 grams of caffeine in a 16 ounce can of Monster.
(For comparison, there is only 34 grams in a 12 ounce can of Coke, 100 mg in a 12 ounce McDonal's coffee, and 150 mg in a 16 ounce Starbucks Latte.)
For those feeling drowsy, caffeine can provide me a pick me up.
Too much caffeine though, can cause lead to a feeling of nervous energy and difficult concentrating - not what you want on a tennis court.
Here is what the USTA booklet on Recovery In Tennis has to say:
"Caffeine is a naturally occurring stimulant
that can be found in coffee, tea, caffeinated
soda, and chocolate in dosages typically
between 30-200mg of caffeine. A large
strong coffee could have more than 200mg
of caffeine. Although caffeine has been
studied extensively in many sports, showing
a multitude of physical improvements in
strength, power, speed and endurance, the
data is limited in tennis players. The few
studies that have been conducted have not
shown positive performance improvements in
tennis players. Recent research on caffeine
and dehydration show limited evidence
of caffeine having a negative response
to thermoregulation or hydration status
in dosages between 300-400mg per day.
However, caffeine is not a supplement that is
recommended for tennis play or competition,
but under appropriate guidance, may have
some positive effects for off-court training
for adult players. Large dosages (>500mg per
day) need to be discouraged, as this could
have detrimental effects on heart rate, fine
motor control, technique, over-arousal and
hydration level. Not enough data is available
on children and thus caffeine should not be a
supplement used by junior tennis players."
, like many words has multiple meanings.
The "energy" in a Cliff bar does not apply to the stimulant effect exhibited by caffeine.
It applies to the caloric energy supplied - calories being a measure of food energy.
Our muscles need the energy from food to move and recover.
The USTA Recovery in Tennis booklet provides information on food to prepare you for play and to help you recover. http://assets.usta.com/assets/1/15/r...es_booklet.pdf