Introduction
Competitive swimming is a sport practised
worldwide and includes swimming events of
varied distances (50–1500 m, 22 s to 16 min) and
stroke styles (freestyle or crawl stroke, back-
stroke, breaststroke and butterfly). Competitive
swimming meets are held year-round and the
age range of the swimmers is between 6 and 80
years. In the United States alone there are
between 1.0 and 1.5 million competitive swim-
mers affiliated with community club teams, high
school teams, college teams, and masters
swimming teams (M.L. Unger, personal
communication).
Each swimming practice session can last up to
about 3 h and may include a total swimming
volume of 10 000 metres or yards. During this
time, swimmers are engaged in various types of
training that include long-distance endurance
training, interval training, sprint training, and
stroke instruction. The specific stroke styles
swum during training depend on the athlete’s
specialty, but most swimmers swim at least 75%
of their total training volume in freestyle. This
training is frequently done twice per day and 6
days per week. In addition to this, many swim-
mers also participate in dry land training such
as strength training or supplemental endurance
running or cycling. Thus, the nutritional
demands of training in this sport can be quite
extraordinary.
Energy demands of
swimming training
The large volume of intensive training of these
athletes imposes a tremendous demand on
energy supply. Sherman and Maglischo (1992)
have estimated the energy requirement of
swimming training at approximately 16.8–
22.6 MJ · day–1(4000–5400 kcal · day–1) for males
working 4 h · day–1 and between 14.2 and
16.8 MJ · day–1(3400–4000 kcal · day–1) for females
working 4 h · day–1. Certainly, these values will
vary considerably according to such factors
as the intensity of the exercises used, the
swimmer’s body mass, and mechanical effi-
ciency. Nevertheless, these high energy needs
can be difficult for swimmers to meet.
Several studies have examined the daily diets
of competitive swimmers to determine if energy
needs are being met. Van Handel et al. (1984)
used diet records to examine the energy intakes
of 14 female and 13 male competitive swimmers
who had competed in the US National Champi-
onhips and were preparing for the Olympic
Trials. Their findings indicate that the energy
intake of the men averaged 18.2 MJ · day–1
(4350 kcal · day–1), with a range between 12.6 and
28.6 MJ · day–1(3010–6830 kcal · day–1). Expressed
relative to body weight, these men were consum-
ing an average of 0.22 MJ · kg–1(50 kcal · kg–1). The
women had energy intakes averaging 9.6 MJ ·
day–1(2300 kcal · day–1), with a range between
6.3 and 13.8 MJ · day–1 (1500–3300 kcal · day–1).
Relative to body weight, these women consumed