Last week we kicked off our four-part question and answer series with My Beauty Life's fitness expert, Brooke Marrone.

This second installment features arm-toning exercises thanks to a query submitted by Anne from Yorba Linda, Calif. who wrote, "Can you please tell how to firm my wobbly arms?"

"Push-ups are the best, most effective way to work every muscle in your upper body and get rid of that jiggle," says Marrone. "This one simple exercise works your biceps, triceps, shoulders, chest, back, and core -- push-ups even help increase metabolism and don't take a lot of time to complete!"

To get the most out of your push-ups, Marrone says to follow these steps: 1. Start with your hands slightly wider than your shoulders and your legs out straight behind you. Keep your legs together and push back with your heels.
2. Keep your core engaged and your body in a strong, straight line with your head as a natural extension of your spine.
3. Make sure you keep your shoulders down and back (not up near your ears) and your abs engaged at all times. Never let your hips drop toward the floor or you will risk injuring your back and putting too much weight on the shoulders.

Note: By changing your arm position you can target the triceps rather than the pectorals or chest muscles. Instead of placing the hands slightly beyond the shoulders and bending elbows out to side, place hands directly under the shoulders and bend elbows in toward the body. Do a few sets of each or do tricep push-ups on one day and chest push-ups on the next.

"Start with three sets of 10 to 15 reps a few times a week," she says, "You will be amazed at how much stronger you'll feel and how much better your arms will look."

Sounds great. Next week? Marrone will show us how to tighten our abs without doing a single sit-up or crunch.