A combination of strength and anaerobic
conditioning, as appropriate to sprinters, results
in some hypertrophy and an increase in the
anaerobic metabolic capabilities of type II fibres.
The resting concentrations of ATP and PCr
increase as well as the capability of the cells to
produce force and power with energy from
anaerobic glycolysis.
In both strength conditioning and combination
strength/anaerobic conditioning, there is little or
no adaptation of the cardiovascular system in
terms of stroke volume, minute volume or blood
composition.
Highly aerobic training involving a large
number of movement repetitions (e.g. 500–2000)
results in adaptations to both muscle cells and to
the cardiovascular system. The aerobic metabolic
capacities of type I fibres is greatly enhanced, as
is, to a lesser extent, the aerobic capacity of type II
fibres. This includes increases in mitochondrial
count, myoglobin content and glycogen storage.
An increase in capillarization provides enhanced
capability for oxygen and substrate delivery and
for carbon dioxide and catabolite removal. The
abilities of the muscle for high force and power
development diminish.
Nutrition of an athlete
All of the factors involving muscle, ventilation/
respiration and circulation are important in
determining the success of a particular individ-
ual in competing in a particular sport. Additional
factors involve coordination (skilled movement),
body size and motivation. However, energy is
needed for the performance of short-term explo-
sive events, long-term endurance events and the
many sport activities that involve the develop-
ment of varying amounts of power during the
course of a contest. Therefore, proper nutrition
must be considered to be a key element to success
in a wide variety of competitive sports.
Frequently overlooked by athletes when con-
sidering the nutrition of sport is the tremendous
time and energy involved in the conditioning
programme between competitions and/or
leading up to a competitive season. Performance
of a throwing event in track and field or of
Olympic weightlifting events takes but a few
seconds of time, but preparation involves many
hours of skill practice and conditioning.
The nutrition of an athlete is a 12-months-of-
the-year consideration. Too often, the focus of
attention is placed on the days or even hours
leading up to a competitive event. While pre-
event food ingestion is of great importance,
optimal health and optimal performance are
dependent on year-around planning. Under
certain circumstances, nutrition during an event
and/or immediately following an event also
carry great importance.
Each athlete must perform at an appropriate
body weight. In addition to the total mass
involved, the relative contribution to total
mass by muscle, fat and bone is of importance.
Optimal values for the various constituents are
best developed through a combination of pro-
per diet and appropriate conditioning that is
continuous.
The moment a competitive event begins, the
athlete should be at appropriate body mass, suf-
ficiently hydrated, possess proper amounts of
vitamins and minerals, and be nourished with
sufficient carbohydrate that an appropriate
balance of carbohydrate and fat metabolism will
provide the energy for the ensuing muscular
activity.Nutritional and energetic limits
to performance
It can be generally accepted that each athlete
enters his/her event with fat stores in excess of
what will be utilized during the course of a com-
petition. It is well known, however, that the
higher the intensity of the muscular activity, the
greater the proportion of energy that the muscles
will obtain from carbohydrate (glucose and
glycogen) compared with that obtained from fat
(fatty acids).
Herein lies a major challenge to athletes
competing in a wide range of sports involving
moderate intensity and long duration, that of
ensuring that the carbohydrate stores in the