Childhood and adolescence

In childhood and adolescence, being active helps to increase the peak bone mass that is eventually achieved.^15,16 Physical activity is extremely important in maintaining healthy bones.

Children should be encouraged to:

• walk to school or the bus stop (where safe to do so) ie. look at walking school bus programs: www.walkingschoolbus.org/
• participate in structured sports (sports involving jumping from different angles, running, skipping and lifting appear to have the greatest impact on bone)
• play outdoors (where safe to do so)

Sedentary activities such as watching television, playing video games and using computers have increasingly replaced physical activity. Parents and carers can help promote participation by doing physical activities with their children.

Adults

In the adult years physical activity is also beneficial for bone health even though peak bone mass has already been achieved. Being active is beneficial in a number of ways as it increases muscle strength,^17,18,19 and assists with posture, balance and coordination which all helps reduce the likelihood of falls.²⁰

Evidence indicates that if individuals continue some form of physical activity into old age and extreme old age (80 and 90’s) whether it is Tai Chi or walking, then the risk of falls is reduced. Further benefits of being active include improvement in cardiovascular health and self-confidence. All forms of physical activity are beneficial for general health and well being. However, there are specific types of physical activities, which can improve bone health.

Physical activities which are beneficial for bone health

Strength training

These activities are also known as resistance exercises. Strength training uses weights of some kind for example machines, dumbbells, ankle or wrist weights, to create resistance which helps build muscle mass and places a load (force) on the involved limb bones.

It also includes activities, which use one’s own body weight as the load (eg. push-ups, whereby the load is placed through the arms and shoulders).

Load placed on bone leads to increased bone formation at the site where the load is greatest.²¹ The benefit is site specific so that if for example you are using weights on your legs, it is only benefiting the leg bones.²² Ideally strength-training programs should be performed regularly, 2-3 times per week. Strength training is most beneficial when a small number of repetitions ie. 8-12 are used and the weight is progressively increased. As strength improves, it is best to increase the weight used in the activities rather than the repetitions.

Weight-bearing and High impact activities

Weight bearing activity refers to exercises, which are performed in the standing position and involves loads (forces) being placed through the feet, which are transmitted up the leg bones and spine. Examples of weight-bearing exercise include walking, running, tennis and dancing. Studies to evaluate the effects of activities such as walking have not shown as drastic an improvement in bone mass unless this activity is performed as a high intensity activity (eg walking at a fast pace, jogging etc).²³

High impact exercises generally refers to weight bearing exercise which involves more load placed through the leg bones and spine during landing after lifting ones own body weight off the ground. Examples of this includes running, skipping, jumping, team sports (eg netball) and high impact aerobics.

There is evidence to suggest that both high impact loading and resistance type (strength training) activities probably provides the most benefit for improving bone mineral density.^21-27 However, there are no studies evaluating whether these actually reduce the incidence of fractures.²⁸

Types of physical activities with minimal effects on bone health

Bike riding and swimming where there is minimal load placed on bone has minimal effect in improving bone mass. However, these types of activities are beneficial in terms of improving cardiovascular health and muscle strength.²⁹

Other good resources

Arthritis Victoria has a register of metropolitan and rural strength training programs conducted by health and fitness professionals who have completed professional development courses run by Arthritis Victoria. To locate your nearest class phone (03) 8531 8000 or 1800 011 041

Content updated July 27, 2009