If you tend to watch the clock during workouts that seem to drag on, you'll be happy to know that a quick 20-minute or 30-minute workout routine can be just as good-if not better. Last week, the New York Times reported on a few "express" classes that reduce workout time by revving up intensity. We've rounded up the top 7 reasons why shorter workouts are long on results:

1. Burn more fat-all day. "Making your workouts shorter and more intense not only saves time, but can also burn more calories overall," says Jari Love, star of the "Get Extremely Ripped Boot Camp" DVD. Shorter workouts often involve quick movements and rapid muscle contractions, which tap into carbs as a fuel source. "When your heart rate is elevated to the point that you are burning carbs primarily, it means you will burn more fat during the workout and even after the workout is over."

2. Build muscle. Our 'fast-twitch' fiber muscles-the ones recruited during quick, rapid movements-are "crucial for muscle strength, speed and power," says Love. When you need a quick break during the workout, switch to more deliberate 'slow-twitch' moves, like squats or crunches; they'll help round out your muscle workout.

3. Strengthen your heart. Getting your heart elevated for 20 or 30 minutes every day will make it stronger and healthier, according to Love. Check out our round-up of quick cardio routines.

4. Prevent injury. "When you train your body to be able to handle fast and sudden movement, you will be better prepared for day-to-day activities," says Love. Plus, a shorter workout means less of the wear-and-tear that leads to sore muscles.

5. Bust excuses. You may not be able to commit a whole afternoon to the gym. But half an hour-or less-of working out is easy to squeeze into even the busiest day.

6. Maximize your time. The best quick workouts help you "multitask" with moves that hit several muscle groups in succession, like lunges with bicep curls or squats followed by an overhead press. And "express" workouts kick up the intensity to speed your trip to the fat-burning zone.

7. Sharpen your focus. "I often see students holding back during an hour class, so worried about pacing themselves that they never give it their all," says Donald Hunter, a cardio kickbox instructor in Rochester. "Knowing a workout is shorter means you're more likely to give it your all, right from the get-go."

Melissa Pheterson is a health and fitness writer and trend-spotter. Follow her on and on Twitter @preggersaspie.

Recommended for You