Growing Up Healthy: Musculoskeletal Milestones in the Teenage Years

Most of us are familiar with the “growth spurt” that occurs during adolescence. In fact, this surge in height is one of the first signs that puberty has begun and signals hormonal changes in both boys and girls. At the peak of this growth spurt, girls grow about 3.5 inches per year, and boys about 4.1 inches per year. However, girls progress more rapidly than boys and usually start the growth spurt earlier and finish about 2 years sooner.

Milestones

The changes teens experience include not only skeletal and muscular growth but also changes in the size of internal organs and body fat levels. During puberty, girls’ body fat increases more than boys’, and in both genders, the heart grows, heart rate decreases, and the capacity of the lungs increases.

In terms of muscular changes, increases in testosterone cause a muscular growth spurt in boys, usually later than the girls’ growth spurt. In normal growth, more general functions of the limbs are established before more specific or fine motor skills. This is known as the “proximodistal trend” of growth.

The growth spurt typically lasts 24-36 months, and weight gain during this period usually represents about 50% of an adult’s healthy body weight. Peak bone mass is achieved in early adulthood.

Potential Musculoskeletal Problems

Unfortunately, the growth spurt adolescents experience isn’t always uniform, meaning that some part of the body will grow faster than other parts. These uneven changes can lead to discomfort and clumsiness that can sometimes  magnify the self-consciousness teenagers often feel. Typically, the arms and legs grow sooner than the rest of the body.

A 2013 Australian study on hormonal changes and knee and lower limb strength and flexibility in teens found that the rapid changes during the teenage years might increase the risk of injury in girls, particularly injuries to the anterior cruciate ligament.

It makes sense that the body’s tendency during and after periods of rapid growth is to develop more general functions and gross motor skills before fine motor skills. This prioritization along the teenage body’s learning curve can increase the risk of injury to teens as they practice sports or other activities that require more balance and specialized coordination.

Scoliosis, or excess curvature of the spine, is also often detected during adolescence. Girls are more commonly affected than boys, and it begins between the ages of 10 and 15. Mild scoliosis may not require treatment, but curvatures over 20% may require intervention in order to prevent back pain, posture problems and several other potentially serious health conditions later on.

Modern Threats to Teenage Musculoskeletal Health

In this day and age, it’s especially important for parents to be alert to the effects that many popular teenage distractions can have on their sons’ and daughters’ musculoskeletal health. Hours of computer game playing can lead to carpal tunnel syndrome, and hunching over a mobile phone late at night can lead to “text neck”. It’s also becoming increasingly common for teens to skip exercise in favor of sedentary, screen-based activities. Given the prevailing trend, parents should do what they can to limit seated pursuits and encourage a wide range of physical activities. Of course, this means parents must practice what they preach, perhaps limiting their own screen time. This sort of simple change can help teenagers “grow into” their new bodies while laying the foundation for good lifestyle habits that can last a lifetime. Plus they provide health benefits to the whole family!