Having a friend to train with is one of the best ways to stick to a program, Siebers says, even if he or she is a cyber-pal.
"Internet chat rooms and support groups really help to motivate," she says.
"It's preventative for [bone-thinning] osteoporosis and other problems." Studies from the CDC have found that muscle-building exercise can also improve balance, reduce the likelihood of falls, improve blood-sugar control, and improve sleep and mental health. Not only does it make you look trimmer and shapelier, but building muscle also helps you burn calories -- even after your workout is done.
"Three to four hours after a strength-training workout, you're still burning calories," says Seibers, a creator of fitness videos including the "Slim in 6" series.
For the arms and upper body, try these exercises: And don't forget to work on strengthening your "core" muscles -- the ones in your abdominal and lower back area.
Core stability is key to avoiding injury, according to Carver.
Success comes from structure and constant support, according to Siebers.