My 17-year old son hurt his back during a soccer practice. He pretty much thinks he is invincible at this age. He does seem pretty strong. We've always joked all that testosterone is protecting him. Is there any truth to this idea?

Athletes ages 13 to 18 may actually be at increased risk for injury due to the hormones circulating throughout the body. Male hormones called androgens are present in both males and females. Women (and girls) have much smaller amounts compared to men (and boys).

Testosterone is the most commonly known androgen. Androgens function as steroids in the body. They build muscle mass, develop male characteristics, and inhibit fat formation. Androgen levels can also influence brain activity leading to aggressive behavior.

Elevated levels of androgens in the adolescent athlete can lead to injury from overuse or repetitive activity. Increased power, mass, and speed from the effects of androgens may overload the adolescent skeleton and joints. Poor posture (so common in this age group) may be a factor. Poor posture combined with weakness puts more stress on the back muscles, possibly leading to injury.

If the force of muscles contracting over and over is greater than the strength of the bone, then fatigue or failure can occur. The end-result is an injury. So although testosterone builds mass and strength, there is a limit to what the body can handle, especially at this age.

Until boys and girls grow in to their hormones, there is an increased risk of activity- and sports-related injuries.