Sep 13, 2002
NEW YORK (Reuters Health) -
Supporting the notion that weight-bearing exercise throughout life can cut the
risk of brittle bones later on, a small study shows that young female gymnasts
build bone mass at a higher-than-average rate.
Researchers found that girls in competitive gymnastics gained more bone density
over 3 years than their non-gymnast peers did. They also put on more lean body
mass, which comes mainly in the form of muscle.
Higher-than-average bone mass has also been found in adult gymnasts, and the new
findings suggest they may owe this to gains made throughout childhood and
adolescence, according to the study authors.
More importantly, such early accumulation of bone density may protect against
fractures later in life, they reported in a recent issue of the Journal of
Pediatrics.
In the US, it is estimated that half of women older than 50 will sustain a
fracture due to the brittle-bone disease osteoporosis. Experts believe that one
way to prevent osteoporosis is to build bone mass at a young age through regular
exercise, particularly so-called "high-load" activities that put more pressure
on the bones to work. Gymnastics is one such activity.
In the new study, Emma M. Laing of the University of Georgia, Athens, and her
colleagues followed 7 female gymnasts and 10 non-gymnasts over 3 years. At the
start of the study, girls in both groups were around 11 years old, on average,
and were of a similar weight and height overall. The non-gymnasts were active in
other ways, with some regularly participating in basketball, softball, soccer or
tennis.
The gymnasts, however, had a higher bone density in the hip, lower spine and
thigh, as well as a lower percentage of body fat. And over the 3 years, gymnasts
accumulated bone density in several areas at a higher rate than the other
girls.
There was no difference between the groups in calcium intake, another important
factor in bone mass, the researchers note.
They also point out that previous studies have suggested that female gymnasts
have a higher-than-average bone density despite the fact that zealous dieting,
delayed growth and irregular menstruation--all of which can signal trouble for
the bones--are problems in the sport.
Laing and colleagues suggest that gymnasts' greater accumulation of muscle,
which exerts a force on bone during contraction, may explain their sturdier
bones.
SOURCE: Journal of Pediatrics 2002;141:211-216.