Child obesity is a huge problem, so if your kids want to start tagging along with you to the gym, you should let them -- it's a great way to build healthy habits at an influential age. But here's the thing -- Kids won't be able to build strong muscles until puberty hits, so the emphasis should be on their form. They can improve muscle tone but they won't be able to bulk up -- and trying to can put them at a risk for injury.

With the help of a personal trainer, youngsters can use light weights to improve their posture and muscle tone, and it's a good introduction to a life of healthy habits. But check with your gym first -- some have age minimums.

Do you work out with your kids?