The human skeleton appears to respond more favorably to physical
activity during the childhood "growth years" than in adulthood.
Previous research has shown 10-20% higher peak bone
mineral density (BMD) in young people who exercise compared
with nonexercisers. In contrast, this figure is only 1-5%
higher in adults who exercise regularly compared with sedentary
If exercise is to be recommended during childhood, gains
in bone density must be maintained in later life, particularly
with respect to the risk of suffering fractures. To investigate
this premise, the authors of a study published in The Lancet
measured BMD in 22 active soccer players, 128 former soccer
players, and 138 age-matched control subjects. Frequency of
fractures was also assessed in 284 additional former soccer
players and 586 controls.
Results: Leg BMD was significantly higher in active
soccer players and former soccer players retired for five
years or less. However, these increases declined with more
lengthy retirement, such that players retired for 35 years
or more had similar BMD levels as control subjects. Additionally,
the separate analysis of fracture rates showed no difference
between former athletes and controls.
If you have children, talk to them about the benefits of
regular, moderate exercise, but remember: consistency is the
key. As these results suggest, maintaining bone mineral density
and avoiding debilitating bone fractures is a lifelong challenge.
For online information on exercise and fitness, visit http://www.chiroweb.com/tyh/sports.html.
Karlsson MK, Linden C, Karlsson C, et al. Exercise during
growth and bone mineral density and fractures in old age.
The Lancet, Feb. 5, 2000: Vol. 355, pp469-70.