As kids grow up, it's healthy and fun for them to compete in sports such as soccer, baseball, basketball, gymnastics, football and even extreme sports, including mountain biking, BMX and skateboarding. But while all that physical activity is beneficial for growing bodies, there is the chance of getting hurt. Consider your child's age when assessing whether their activities could hurt them. The old adage, "The bigger they are, the harder they fall" definitely applies when it comes to kids, particularly those in contact sports like football. As they age, children obviously get larger and better able to inflict harm, albeit accidentally. And football is the number-one sport for injuries in kids under the age of 18, followed by basketball. Up to two thirds of injuries are sprains and strains, while fractures make up only about 5 percent of sports injuries. Other aches and pains that arise may be a result of overuse, which occur when a certain movement is repeated.