NUTRITION IN SPORT - Index of

Q . ), the total circulating haemoglobin and the
capillarization of the skeletal muscles that are
involved. Such conditioning also serves to
enhance the aerobic metabolic capacities of the
skeletal muscle cells including both type I and
type II fibres.
The programme would consist of a combination
of interval training and some extended
bouts of exercise (e.g. 10–60 min) consistent with
the particular competitive event. Depending
upon the individual athlete and the point in time
relative to the competitive season, the athlete will
train vigorously three to seven times per week.
It is important to note that such aerobic conditioning
can adversely affect the particular skeletal
muscles involved as regards the ability for the
generation of high power and the explosive
effort involved in activities such as jumping and
throwing. The adaptation of the systems of the
body and, in particular, the skeletal muscles will
be specific to the conditioning stimulus or, in
other words, the conditioning programme.
Anaerobic conditioning
For events lasting less than 10 min, energy
obtained from anaerobic glycolysis is an important
factor; the shorter the event the greater is the
contribution of this source. There is an obvious
overlapping with oxidative metabolism the
longer the duration of the activity.
With a programme of conditioning that combines
a considerable amount of strength training
with very high but continuous exercise intensity
that mimics the event (e.g. the 100-m run, the
100-m swim, wrestling), the emphasis is on an
appropriate increase in the size of type II muscle
cells, enhancing the capability of the cells for
anaerobic glycolysis, and increasing the concentrations
of ATP and PCr. Most, if not all, type IIb
fibres that exist at the initiation of such conditioning
convert to type IIa. Except for the shortest
lasting performances (weightlifting, high jump,
pole vault, discus, shot-put, javelin), maintenance
of high concentrations of glycogen in
the muscle cells through proper nutrition is
important.
basic exercise physiology 13
Strength conditioning
Increases in maximum force production
(strength) and maximal power of the muscles are
brought about through exercise programmes of
very high opposing force (routinely termed
‘resistance’) that limits repetitions to approximately
20 or fewer and therefore a duration of
less than 30s. Exercise programmes based on
higher repetitions (e.g. 30–50 repetitions leading
to exhaustion) develop local muscular endurance
but are not conducive to strength development.
Exercise involving many repetitions
in a bout (e.g. 400–1000 repetitions) brings
about physiological adaptations that result in
enhanced aerobic performance that can be especially
counterproductive to power development
and, to a lesser extent, on the performance of
strength tests.
‘Resistance training’ is performed with a
variety of exercise machines, free weights or
even the use of gravity acting upon the athlete’s
body mass. Most resistance training (strength)
programmes are based on a system of exercise to
a repetition maximum (RM) as presented in the
mid-1940s by DeLorme (1945). Every time the
athlete performs a particular exercise, the bout is
performed for the maximum number of repetitions,
or RM, possible and this number is
recorded along with the mass lifted or opposing
force imposed by an exercise machine. Repeated
testing at increasingly higher opposing force will
eventually lead to the determination of a 1RM, in
which the athlete can perform the movement but
once and not repeat it. In this system, the mass
lifted or opposing force is described as the
athlete’s strength at that particular point in time
and for the particular movement.
Bouts of strength exercise and the daily programme
can be based on percentages of a 1 RM,
preferably, within heavy (3–5), medium (9–10)
and light (15–18) RM zones (Fleck & Kraemer
1997). The number of bouts performed in a set,
the number of sets performed per day and the
number of daily workouts per week are then prescribed
for each movement or muscle group as
based on the point in time in the competitive