Moderate resistance training is beneficial, but young boys shouldn't work out in an effort to bulk up, he says. Young people should never attempt repetition maximum lifts. It can only cause damage and won't help prepubescent boys develop enlarged muscles since they don't have sufficient hormones necessary to build muscle size. Prepubescent boys are very similar to females in that they can develop strength and tone their muscles, but their muscles won't get a lot larger. This benefit will not be recognized until after puberty.
Similar recommendations apply to prepubescent creatine use.
In an attempt to improve their physiques, young people are attracted to dietary supplements such as creatine, a synthetic version of a substance created in the liver and kidneys that can be converted to testosterone in the body. Creatine use has become widespread even among high schoolers in order to get more dramatic results from workouts, says Darden. But since the supplement interacts with male hormones, it may not be very effective before puberty. As a new supplement, there's too much unknown about it to promote it as a supplemental aid. We need to wait on long-term studies to really understand the potential negative effects of creatine.