Measuring bone size and strength

The study, published in the Journal of Clinical Endocrinology and Metabolism, included 1,748 boys and girls. They are part of a large ongoing study examining the factors affecting the health, growth, and development of children beginning at birth. The data used for this report was collected at their 15.5-year physical examination.

Researchers measured the teens’ bone mass and density through a test that determines the geometry and strength of a bone as well as its mass and density (peripheral quantitative computed tomography). They were each given an accelerometer, a device that measures the amount and intensity of physical activity, to wear for seven days.

Vigourous exercise builds bone

After examining the data they collected, the researchers found:

• Light and moderate physical activity had little bearing on bone mass.
• Only the children who engaged in vigourous physical activity had higher bone mass.
• Vigourous exercisers also had more bone volume and greater bone strength.

“Our findings suggest that adolescent participation in vigourous physical activity, but not moderate physical activity or light physical activity, may have long-term benefits for skeletal health,” researchers summarized.

Keeping bone all your life

During childhood and young adulthood, we build new bone faster than we break down old bone. But after about age 30, the trend reverses and we begin to slowly lose more bone than we build. Having more bone mass at the time this reversal occurs makes it less likely that we will develop osteoporosis in our senior years.

The results from this study show that intense exercise accelerated the building of bone mass in adolescence. Moderate and light exercise didn’t show the same protective effect, but any physical activity could still be important in establishing a healthy habit that will prevent bone loss in middle and old age.

Help your children keep their bones healthy throughout life by encouraging good habits, like engaging in regular exercise and following these other tips:

• Eat a mineral-rich diet. This includes green vegetables, nuts and seeds, tinned fish with bones, tofu and other soya foods, as well as some dairy foods.
• Cut out colas. These fizzy drinks are high in phosphoric acid and caffeine, both of which can increase calcium loss.
• Don’t smoke. Smoking increases osteoporosis risk.
• Take vitamin D. Most doctors recommend that children and adults supplement with vitamin D, especially those who live in northern latitudes and particularly in winter.