by choosing multi-muscle movements that burn lots of calories, but that also simultaneously train your core, you can truly carve out a washboard.
- Mountain Climber with Pushup
The pushup is a great movement for your chest, shoulders, and triceps. Your core muscles have to work over time to keep your spine stiff. When you combine this classic move with an ab exercise called the mountain climber, it engages your core even more. Try doing to 10 to 12 reps, or simply perform sets for 30 to 60 seconds at a time.
- Turkish Getup
It is a super-simple movement: You lie on your back, holding a kettlebell or dumbbell above one shoulder. Then you simply stand up, while keeping the weight above you at all times. This not only helps build total-body strength, it’s also a great way to torch calories. Do 3 reps — or “getups” — with each arm; rest 60 seconds, and repeat one more time.
- Pushup-Position Row with Squat Thrust
Every time you row one dumbbell, your core muscles have to fight to keep your body stable. Try doing this exercise for 30 to 60 seconds, then rest 30 to 60 seconds and repeat one to two times.
read article on Yahoo! Sports by Adam Campbel from Men’s Health: Three Surprisingly Strong Ab Exercises