Young athletes are not smaller versions of adult athletes and should not be trained in the same manner. There are specific differences in the body structure of a child that increase the risk of sports injuries in the younger population. Some primary differences include the following:
- Children have head to body proportions that create imbalance.
- Children are smaller in size and protective gear may not fit properly.
- Children have open growth plates. Damage to the growth plate can lead to early closure and abnormal growth of the bone. For example, injury to a growth plate around the knee joint may lead to a leg length discrepancy or a change in the alignment of the bone.
- Children lack mature motor skills, which usually do not develop until 10-12 years-old. During puberty, as children experience their growth spurt, a temporary decline in coordination and balance places them at greater risk for falling and sustaining an injury. Overall, they may not have the motor skills required for certain sports until after puberty.
- Children have softer bones and growing cartilage is more sensitive to the force across joints during activity. Both of these factors increase the risk of fracture and injury to the growth plate.
Some tendons attach to a special part of the growth plate in immature bone called the apophysis. In children the apophysis is separated from the main part of the bone. When a muscle contracts tension develops in the muscle-tendon unit and is transmitted to the apophysis. Repetitive pulling at the site of the apophysis creates inflammation, swelling, and pain. This condition is referred to as apophysitis and commonly develops in the elbow (Little League Elbow), the knee (Osgood-Schlatter Disease and Sinding-Larsen-Johansson Disease), and the heel bone, which is also referred to as the calcaneus (Sever disease). When the apophysis fuses to the main bone at the time of skeletal maturity (adulthood), these conditions no longer develop.
Peak height velocity (PHV) is the point in puberty when the tempo of growth is greatest. During this time, children and teenagers experience “growing pains” including conditions such as apophysitis. In general, PHV begins around age 9 in girls and age 11 in boys. As children grow they gain weight and are able to move faster. Their movements become associated with more force, which increases the risk of injury. Overall, the stages of development in each age group influence the capacity to adapt to the stress of athletic activity. Being aware of the differences in development between children, teenagers and adults is an important step in preventing sports injuries.