day–1(1223 or 1495 kcal · day–1), depending on
the technique used to obtain food intake data
(Benardot 1996). These values represent approxi-
mately 60–70% of the recommended intake and
66% of the gymnasts’ predicted energy require-
ment. In this study there was a statistically sig-
nificant relationship between energy intake and
body-fat percentage. Gymnasts with the lowest
energy intake had the highest body fat levels,
and gymnasts with the greatest number of
within-day energy deficits greater than 1255 kJ
(300 kcal) also had the highest body-fat percent-
ages. These data were sufficiently powerful that
body fat could be predicted from the largest
energy deficit (Benardot 1996):
Body fat %DEXA*=Largest energy deficit
(0.00385893)+7.92609
Standard error of estimation=2.438
Multiple R^2 =0.582
P=0.0035
These data suggest that the gymnasts’ adap-
tive mechanism to energy inadequacy is to
increase energy storage (fat), probably through a
decrease in the metabolic rate and a heightened
insulin response to food. These data also support
the idea that regular energy restriction is coun-
terproductive in the attainment of low body fat,
and may create an increasingly difficult cycle of
continually greater food restrictions to maintain
the desired body composition.
A group of older United States college gym-
nasts, averaging 19.7 (±0.2) years of age, reported
an energy intake of 5780 kJ · day–1 (1380 kcal ·
day–1), representing 63% of the RDA and 47% of
the predicted energy expenditure of 12.2 MJ
(2911 kcal) (Kirchner et al. 1995). The difference
between reported energy intake and predicted
energy requirement represents an energy intake
that provided only 47% of the predicted require-
ment for this group. This was the oldest group of
competitive gymnasts studied, and a group
with the greatest average height and weight.
Nevertheless, this group had the greatest differ-
ential between predicted energy expenditure
and energy intake. They also consumed signifi-
cantly less daily energy than age-, height- and
weight-matched non-gymnast controls (5780 vs.
7304 kJ, 1381 vs. 1745 kcal) (Kirchner et al. 1995).
The only reviewed published survey of
energy and nutrient intake in male gymnasts
determined that these athletes had the lowest
energy intake (approximately 8707 kJ · day–1or
2080 kcal · day–1) of college athletes involved in
various college sports (Short & Short 1983). The
other sports evaluated in this survey included
wrestling, basketball, football (American), crew,
track, track and field, lacrosse, football (soccer),
mountain climbing and body building.
A study of 18 former competitive gymnasts
(female), with a mean age of 36.3 years at the time
of the study, were found to consume 10.9 MJ ·
day–1(2620 kcal · day–1) (Kirchner et al. 1996). This
level of intake is 119% of the RDA and 12% higher
than a group of age-, height- and weight-
matched controls (Kirchner et al. 1996). This is a
dramatic departure from the energy intake of
gymnasts who are actively competing, and may
indicate a degree of liberalized eating behaviour
that follows years of restrained eating.Energy substrate distribution
The intake of energy substrates in gymnastics
should be based on usage rate and the associa-
tion of different energy substrates with other
needed nutrients. Because gymnastics activity in
both competition and practice is primarily an-
aerobic, there is a heavy reliance on glycogen and
creatine phosphate as fuels. Glycogen storage is
best accomplished on diets that are high in
starchy carbohydrates. Creatine storage, which
can be synthesized from the amino acids glycine,
arginine and methionine, is best obtained in the
diet through consumption of skeletal muscle
(meat protein) (Crim et al. 1976; Coggan & Coyle
1988). (For information related to creatine me-
tabolism and creatine monohydrate supplemen-
tation, see Chapter 27.)gymnastics 593
- Body fat percentage derived by dual energy X-ray
absorptiometry (DEXA).