19 Life-Changing Secrets

Your Best Body

3. The Secret to... Your Flattest Abs Ever

Keep the contraction constant while doing crunches. "When you lower your back and head to the floor between each move, you rely on your hip flexors or upper back, rather than your abs, to bring your body back up. Making the movement small and tight keeps abdominal muscles active, which maximizes the burn -- and your results."

--David Kirsch, founder of the Madison Square Club in New York City and author of The Ultimate New York Body Plan (McGraw-Hill, 2004)

4. The Secret to... Strong Legs and a Toned Butt

Get a leg up. "Lift one foot an inch or two off the floor as you do your deadlifts, dumbbell shoulder presses, or biceps curls; switch legs before you begin the next set. This helps train and strengthen the leg's smaller, deeper stabilizing muscles, which will make legs look more sculpted. You'll also burn more calories than you would working both legs simultaneously."

--Chris Uy, fitness manager at The Sports Club/LA in New York City

5. The Secret to... Firming Up Really Fast

Be unrealistic. "Pretend to be a celebrity with a big event coming up in three weeks. Commit to an intensive program that combines six days a week of cardio and/or strength training with healthy eating. A 21-day period is doable, and it's enough time to see an increase in definition and endurance and for muscle memory to set in. So even though you've officially 'completed' your program, you'll be inspired to keep going."

--Kacy Duke, celebrity trainer based in New York City

6. The Secret to... Preventing Workout Injuries

Train the way you need your body to move in life. "Constantly doing basic exercises the same way -- lunges and squats, for instance -- creates muscle imbalances that can lead to injury. To counter this, it's crucial to engage muscles you use on an everyday basis in your fitness routine -- even if it's just during your warm-up. As you rise from a squat, lift a ball over your head and then lower it slightly with arms straight, as you might if you were putting a case of soda on a high shelf. When you do lateral side lunges, pick up an exercise ball from the outside of one foot and lower it to the ground on the other."

--Alden Mills, former U.S. Navy SEAL officer and creator of BodyRev, a functional fitness weight system