NUTRITION IN SPORT

Influence of exercise and diet on

a child’s growth and development

Some authors (Martinez et al. 1993; Lindholm et
al.1995) suggest that, in the long term, if chil-
dren’s energy intake is insufficient in relation to
their energy needs, this could affect their growth
and sexual development. It is well recognized
that young female gymnasts are shorter and
lighter than sedentary girls of the same age: they
also show signs of late maturation, as evidenced
by late menarche (Baxter-Jones et al. 1994; Lind-
holmet al. 1994; Malina 1994). Hence, although
there is clear evidence of an effect of intensive
training on the hormones of the hypothalamic–
pituitary axis, it is not clear whether this effect
accounts for what appears to be a loss of growth
potential in some elite young athletes (Theintz
et al. 1993). What is known is that malnutrition
delays growth. Children subjected to episodes of
acute starvation recover more or less completely,
provided the adverse conditions are not too
severe and do not last too long, and will reach
their predicted adult height. Chronic malnutri-
tion, on the other hand, causes individuals to
grow to be smaller adults than they should
(Tanner 1989), but there is no evidence to suggest
that young athletes are malnourished.

432 special considerations

The elite young athlete

It has been demonstrated that, although

restricted energy intake can delay maturation

and sexual development, the late development

which is observed in some sports is more related

to inherited characteristics than to the effects

of intensive training and/or nutritional inad-

equacy. Several studies have compared the phys-

ical characteristics of elite junior performers in

different sports with those of non-elite competi-

tors and non-athletic children (McMiken 1975;

Buckler & Brodie 1977; Bloomfield et al. 1990).

Data from a longitudinal study of young female

British athletes indicated differences in stature

between three sporting groups and UK growth

standards (Fig. 32.2). At all ages, swimmers and

tennis players were above average height on

British growth standard charts (Tanner 1989). In

contrast, gymnasts were below average height,

particularly from 12 to 16 years of age. How-

ever, at 17 years of age, the gymnasts’ height was

again similar to the average height seen on the

standard charts, indicating that what was being

observed was a late attainment of the adolescent

growth spurt. The parents of these gymnasts

were also of less than average height (Baxter-

Jones 1995), in accord with other data (Theintz

175

170

165

160

155

150

145

140

135

130

125

120

115

8 9 10 11 12 13 14 15 16 17 18 19 20

97th

50th

3rd

Age (years)

Stature (cm)

Fig. 32.2Development of stature

in British female athletes

compared with standard growth

percentiles (dotted lines). Means

and standard errors are shown

at each age. Standard growth data

are taken from height percentiles

of British children (Tanner 1989).

, swimming; , tennis; ,

gymnastics. From Baxter-Jones

and Helms (1996), with

permission (based on data from

Tanner 1989).