Q: My 13-year-old son wants to try dumbbells. He is 5ft. 8in. tall and his weight is 126 lbs. Are 15 lbs dumbbells appropriate for him to start with? Please advise! Thank you!

A: Yes, it's perfectly healthy and safe for your son to start weightlifting with light to medium weights. There are a couple of things that are extremely important for you and him to understand however...

First, he needs to learn proper safe form for all the exercises he will perform before he starts piling on weight. He can find videos and descriptions of many common exercises here. He should always perform all exercises with proper form, never violating it to push more weight or for any other reason. This will keep him safe.

Second, related, point is that until he is at least 16 or so he must not push himself to the point of muscular failure on any exercise. That means that for any given exercise he may select a weight he could potentially lift 12 times or so but then only lift it 10 times or so, so he always stops his sets before the point of absolute exhausting. After he rests for a minute or two he can repeat the exercise.

Both of these points will keep your son safe while exercising. Serious weightlifting injuries are not common but should one happen to your son it can stunt his growth. By following proper form and not pushing himself to the limit he will stay safe.

As far as exactly what dummbells to use, certainly, 15-pounders are fine to start with. Eventually as your son hopefully performs different exercises for all his muscle groups (as opposed to just the bicep curls) he will probably want to get a couple other sets of dummbells to keep all the exercises sufficiently (but not too) challenging. For example, he will be able to perform dumbbell rows with heavier dumbbells than bicep curls.