Curls and sit-ups can definitely help tone your abs, but a new study suggests something else might work better.

Seems counterintuitive, but working your upper body may be the quickest path to a really sculpted middle.

Above-the-Belt Action
In a study, women did isometric exercises for their stomach, back, shoulders, and arms while researchers measured muscle activity. The results? Shoulder extensions made middle-body muscles contract most -- apparently they work extra hard to stabilize your trunk when your wings are flapping. (Watch this strength-training video to learn how building 5 extra pounds of muscle could burn 26 pounds of fat in a year.)

Full-Body Fitness
Some more ways to get your midsection -- and whole body -- into mint condition:

• Roll out the ball. For strong core muscles and better balance, do tummy and back toners on an exercise ball. Follow these simple steps.
• Add resistance. Use weights or resistance bands for extra burn. Use this tool to create a 20-minute workout with or without equipment.

Ready to make exercise a multitasking affair? Try these Dirty Dish Dips and Squeaky Clean Squats.