Girls like these U-12 soccer league players have a five- to eight-times-higher risk of suffering certain knee injuries than boys. (Jim TillerAP Photo/Daytona Beach News-Journal)

While children enjoy summer holidays swimming at the cottage or playing ball with friends, parents may already be thinking ahead to tryouts for school sports teams. Either way, experts say it's important to practise injury prevention while having fun.

Injuries are the most significant threat to the health of Canadian children, according to the Canadian Hospitals Injury Reporting and Prevention Program.

Canadian and international research shows there are ways to reduce the risk of getting hurt. Simple warm-ups have been shown to significantly reduce the risk of lower-extremity injuries among teens playing soccer and basketball, said Carolyn Emery, a physiotherapist at the University of Calgary Sport Medicine Centre.

"We are able to reduce the risk of injuries in youth soccer players through implementation of a team-based neuromuscular training warm-up program and home-based balance training program," said Emery, a spokeswoman for the Canadian Physiotherapy Association.

Emery's clinical trial results showed the training program helped reduce the overall injury rate by 38 per cent and acute onset injury rate by 43 per cent in Calgary. She and her colleagues recommended that soccer teams for males and females aged 14 to 18 should include balance training to reduce the risk of injury.

To achieve those results, a physiotherapist initially taught the program to coaches, trainers and players, and then followed up to facilitate proper technique and track participants. A coach or trainer delivered the program, which included:

• Balance components such as soccer-specific exercises on a wobble board.
• Agility training, with a focus on jumping and landing techniques.
• Strength training.

The program was moderate in intensity, to encourage physiological warm-up before hitting the pitch.

Players were also expected to balance on the wobble board at home for 15 minutes, three times per week.

The Toronto High Park U-12 Hurricanes take 15 minutes at the start of every soccer drill to build up their motor control. Their program is from FIFA, soccer's international governing body, and was modified by a local sports medicine clinic for the girl's rep team.

"It's fun," said soccer player Hannah Turnball after a drill that included taking large steps and alternating touching the grass with each knee. "It's tiring and it's sometimes hard to do different stretches in different ways."

Costly knee injuries

The exercises are not too rigorous or different from their previous warm-up routine, but the exercises are targeted toward building up muscle control to help protect the girls' knees. In July 2009, the team was half way up the learning curve to master them, said coach Marius Locke.

Injuries like a tear of the anterior cruciate ligament or ACL, which helps to anchor the knee, can occur from activities that require athletes to jump or pivot.

ACL injuries have gone from "a guy's football injury" in the 1950s to one that occurs in children more often as their participation in sports like soccer, basketball and volleyball has increased, said Theodore Ganley, director of the Sports Medicine and Performance Center at The Children's Hospital of Philadelphia.

Studies suggest that girls have between a five- to eight-times-higher risk of suffering ACL injuries than boys, said Dinah Hampson of the Canadian Physiotherapy Association.

"There's a lot of speculation, but nobody's really sure," said Hampson. "It could be because of the knee design, it could be because of hormones."

ACL injuries can lead to ligament tears around the knee or other injuries, and are considered a rising public health problem as well as a costly strain on the medical system.

Once the costs of rehab, arthritis and potential knee replacement and ACL reconstruction are factored in, an ACL-torn knee can cost $100,000 to $200,000 during a patient's lifespan, said Hampson.

Tips for parents

Parents can help to prevent injuries by actively ensuring their children have the equipment, nutrition and hydration they need to play safely, said Mike Yates, a sport physiotherapist who coordinates a teen injury prevention program in Penticton, B.C.

That means wearing helmets for cycling and skateboarding, wearing footwear that matches the sport and playing surface, eating a carbohydrate-based athlete’s diet with minimal pop and junk food, and drinking eight ounces of water every 20 minutes in hot conditions, said Yates, a CPA spokesperson.

He also suggested that parents can encourage their children to:

• Perform training and conditioning (cardiovascular, muscle strength, balance).
• Do dynamic stretching (actively moving, such as controlled leg and arm swings, that move a joint through its range of motion) before an activity, and work on static stretching (reaching forward to a point of tension and holding the stretch) afterwards.
• Practise techniques and skills (landing a jump, cutting and pivoting).
• Ensure rest and recovery after activity (rehydrating, renourishing, stretch and cool down).