Exercise for strong bones

A calcium-rich diet is good for bones, but a new study has found that regular workouts can be just as useful

Warming up before regular PE lessons can improve bone health in teenagers, according to a study published in the September issue of the Journal of Bone and Mineral Research.

Researchers from the School of Physiotherapy and Exercise Science at Griffith University, Australia, incorporated 10 minutes of warm-up activities twice a week for eight months among 99 teenagers in their Power PE study.

Students worked up to 300 jumps per session, and a series of repetitions of star jumps, tuck jumps, side lunges, hops and skips were designed to apply a load on the skeleton aimed at stimulating bone growth.

By the end of the study period, whole body mass was improved among boys while girls' bone mass specifically improved at the hip and spine.

Invest in healthy bones

Bone is a living tissue, which means it's continuously being recreated - old bone is broken down and replaced by new bone.

The replacement of old bone takes place throughout our lives. However, from age 30 to 35 onwards, more bone is lost than can be replaced by new, which means our bones get weaker.

During adolescence the skeleton is actively growing and getting bigger and stronger. By the end of our teens bone growth is completed. This is when our bones have achieved their 'peak bone mass' and are at their strongest.

The higher the peak bone mass you achieve at a young age, the greater protection your skeleton will have against bone loss and osteoporosis - brittle bone disease.

Peak bone mass is influenced by our genes and whether we're male or female. It can be increased by eating enough calcium and vitamins when we're young, as well as by doing exercises such as jumping, running, dancing, walking and climbing stairs.

Invest in healthy bones now. Think of your skeleton as a savings account. You need to deposit calcium into your bone when you are young.

Eat your way to healthy bones

Dairy foods such as milk, yoghurt and cheese are rich sources of calcium. Calcium fortified breakfast cereals and soya milk, tofu, nuts, dried fruit, green vegetables and fish are also a good source. Teens should include at least three servings of calcium rich foods in their daily diet for example, a few glasses of low fat milk and a pot of yoghurt. Use it or lose it

Weight bearing exercises build denser and stronger bones, which will be helpful in later life.

Growing bone is especially sensitive to the impact of weight and muscle pulling on bone during exercise.

Muscle pulling on bone helps to build bone, which is why it's so important to be physically active every day.

The best exercises for building bone strength are weight- or load-bearing exercises, and these include jumping, side lunges, skipping, weight-lifting, jogging, hiking, stair-climbing, step aerobics, dancing, tennis, badminton, squash and other exercises that require your muscles to work against gravity.

The Griffith University study provides good evidence that plenty of exercise while young is extremely good for bone mass.

The study also shows weight-bearing activities can easily be incorporated into PE lessons twice a week, something Hong Kong schools should be encouraging.