HOW TO PREVENT CANCERS

by Lakshmi Singh

Children need a range of physical activity - and lots of it - to keep them fit strong and healthy.

Do your children play sport on the weekend, regularly swim in the pool or surf, ride their bikes, climb trees, or kick a ball around the backyard?

Children need to be physically active. It helps improve their sleep, posture, concentration, behaviour, and reduces their chances of becoming overweight or obese, which increases their chances of developing a range of serious health issues later in life.

Australia's physically activity guidelines recommend that toddlers (between the ages of 1-3) and pre-schoolers (between the ages of 3-5) spend at least three hours a day being physically active. The level of activity can range from simply standing up and moving around to active play – such as Simon says, hide and seek, or playing chasing – and other vigorous activities, including running or jumping.

Older children, aged five and older, need to do a combination of moderate and vigorous activity for at least 60 minutes a day, but more is better.

However, the 2011-2012 Australian Health Survey suggest many Australian children aren't getting the activity they need, with 72 per cent of children between the ages of two and four are getting the recommended three hours of physical activity every day, only 19 per cent of the five to 17 year olds are physically active for an hour each day.

But what type of physical activity do young children need, and how can you help to make sure they get it?

Tell your kids to do some aerobic activity and they will probably just look at you with a confused look on their face (or possibly do some star jumps). But bike riding, jogging, walking, skipping, swimming, and playing soccer or football are all aerobic activities many kids enjoy.

Any activity that involves large muscle groups is defined as aerobic activity, says Liz Ernst, Exercise Physiologist at Wesley Life Shape Clinic.

"In order to use fat stores as energy, the body and muscles rely on the transportation of oxygen to the working muscles," she says. "It is generally low intensity exercise that increases the heart rate to 65-75 per cent of maximum heart rate." (Maximum heart rate, the number of beats per minute of the heart when working at its maximum, can be esitmated as 220 minus your age.)

Increasing your heart rate in this way means your heart and lungs are working harder, and this helps keep them stay in top shape.

Dr Carolyn Broderick, staff specialist Sport & Exercise Medicine at The Children's Hospital at Westmead says, doing regular aerobic activity at any age, helps to reduce your risk of developing of a range of chronic disease, including cardiovascular disease, type 2 diabetes and hypertension (high blood pressure).

Regular areobic activity can also help improve children's behaviour, mental health, academic performance and thinking ability, with studies recently revealing a positive association between the two.

Another good reason to encourage your children to enjoy a range of regular physical activities from an early age is that it sets them up for better exercise habits throughout life.

"Children and adolescents who are physically active are more likely to be physically active as adults," she says.

60 minutes of moderate-intensity exercise daily, 20-60 minute of vigorous-intensity exercise (3 days/week)

On their own: riding bikes, running around outside, dancing , swimming, frisbee, skating

For the whole family: Active trips to the beach, zoo and park. Household activities like walking the dog, washing the car and mowing the lawn.

Weight-bearing exercise places stress on your bones and helps to build bone mass.

As children don't usually achieve peak bone mass until the late teenage years or early 20s, loading of bones through weight-bearing exercise and muscle strengthening is critical for this process, Broderick says.

"Prolonged periods of immobilisation or reduced weight-bearing physical activity during these years (particularly the peri-pubertal years) can result in children not achieving their genetic potential for bone mass/density. This becomes very important later in life when density of bone declines and fracture risk increases," she says.

Simple backyard activities such as skipping star jumps and running contribute to your child being able to maintain strong and healthy bones, she says.

Two to three times a week.

On their own: Games such as hop-scotch, riding bikes, running around outside, dancing, swimming, gymnastics, jump rope, hopping, martial arts training

For the whole family: Playing basketball, netball or tennis at a local court, dancing at a family disco night, jogging or bushwalking (especially up hills).

As the name suggests, muscle strengthening helps make kids' muscles stronger, which can help protect muscles and joints from injury and also help kids to perform better when taking part in sporting activities.

"Placing small stresses on the muscle will generate a feedback loop to build muscle mass and therefore strength," says Ernst.

When you do muscle strengthening exercises, you are making the muscle work against a resistance – be it body weight, water or machines, which will result in micro-tears in the muscle. This then sends a signal to your brain that allows for energy to be delivered to help the muscle repair and grow, she says. It's not recommended that under the age of 16 children do weight training in a gym in the same way that adults do, but there are a range of activities that can help children to build muscle.

"Children should not perform maximal lifts until they have reached skeletalmaturity (which is usually at about 16 years of age). They should use age-appropriate strength equipment and have a gradual progression of loads. In children, weight training generally consists of higher repetitions but lower loads than would be used in adults," Broderick says.

There are muscle strengthening programs – such as Cross Fit – specifically designed for children. You might find such a program at a local gym, PCYC or sports club.

Two to three times a week on non-consecutive days.

On their own: climbing – trees and playground equipment, walking lunges, horse riding, dancing, games such as tug-of-war, modified push-ups (with knees on the floor), sit-ups.

For the whole family: Racquet sports, rock climbing, swimming, bike rides in hilly areas, gardening activities like digging and pruning, aqua aerobics and structured classes that use the body as resistance like Pilates or yoga.

Stretching can help ensure your muscles remain at their optimum length, this ensures your joints can move through their entire range and helps reduce the risk of sprains and strains, says Ernst.

"Kids generally have increased flexibility; being too flexible can also cause injury. So it's best to stretch the muscles which are most tight," she says.

Tight muscles can also affect posture, she adds. To avoid problems caused by bad posture, it's important to encourage children to stretch regularly, especially after they have been sitting and reading or watching a screen for a long period.

Ernst recommends hamstring, shoulder and neck stretches at regular intervals when in front of the computer and/or sitting for prolonged periods.

Also as children grow their bones may outgrow their muscles, which can cause tightness, and sometimes in adolescents this can cause growth-related conditions that cause pain, Broderick says. One such condition is Osgood-Schlatter disease, which causes pain and/or swelling at the front of the knee.

"Stretching exercises are useful to alleviate this condition and may have an important role in the prevention of these conditions," she says.

Two sets of 30 second to one minute stretches, two to three days per week for each muscle group, or for five to ten minutes per muscle group after aerobic exercise.

On their own: Kids can be taught targeted stretches to help stretch tight muscles, especially after sitting for long periods. These include:

Hamstring stretch – sitting on a chair, knees bent at 90 degrees. Straighten one leg out so the heel is on the ground (keep a slight bend in the knee), reach forwards from the hips feeling the stretch behind the upper part of your leg.Chest: Standing in a door frame, place forearm on the frame so your elbow is at shoulder height, take a step forward to feel the stretch in front of the shoulderNeck: Tilting head to one side, hold to feel the stretch on the opposite side to where your head is tilted

For the whole family: Raking the backyard, family yoga, Pilates and stretching classes.

Published 28/11/2013