Country-music star Carrie Underwood, 31, is packing some serious strength. She even tweeted a picture of herself doing chin-ups! Find them too challenging? Carrie's trainer, Erin Oprea, suggests Band-Assisted Chin-Ups. "They work the same muscles—your lats and biceps—as the full-weight kind," she says.

Here’s how to do it: Loop and secure a resistance band over a sturdy bar (like a pull-up bar or playground monkey bars) and place a foot in the loop. Hold the bar with an underhand grip, your hands shoulder-width apart (A). With your abs engaged, bend your elbows and pull your body up until your chin is above the bar (B). Slowly lower back down. Do 4 sets of 5 reps 2 to 3 times a week.

RELATED: 11 Moves to Get Strong, Toned Arms