剛找個這個，據說plank很有效

The plank

Lie face down on the ground
Lift yourself up into your elbows whilst keeping your feet on the ground toes pointing to the floor.
Keep your body aligned straight, pulling in your belly button inwards
Hold this position for 30.
Work your way up to 90 seconds as you improve.

This exercise works all the core muscles and keeps your spine stable and straight. You will not be putting less strain on your back compared to crunches or sit-ups.

Mountain climber with exercise ball

Go into push-up position on the exercise ball
Bend one leg towards your chest, bringing your knee up, hold for a second and lower back to the ground.
Keep your back straight.
Repeat again for the other leg.
Do 20 reps where raising one leg to your chest is one set.

This exercise works your core muscles as with the plank exercises. You also increase the stability workout for the muscles in your core, arms and legs.

 

Stability roll outs with exercise ball

Kneeling on the ground in an upright position. Your hands out in front of you resting on the exercise ball.
Roll the ball out in front of your so that your arms are extending. Roll out as far as you can and hold for 2 - 3 seconds
Keep your stomach pulled in and your back straight at all times.
Pull yourself back to the starting position.

This exercise works your core and lower back stability muscles as well as working your abs. Although your lower back is getting a workout, it is not put under any strain.

Exercise ball jackknife

Roll yourself on your stomach over the exercise ball so that your hands are shoulder length apart on the floor and your shins and feet resting on the exercise ball.
Keep your arms and back straight pulling your belly button in.
Roll the exercise ball towards your chest raising your hips and rounding your back. Pull the ball until your feet are on the ball. Pause and return to the start position.

Russian twists with exercise ball

Sit on the exercise ball and roll yourself onto your back. Move your feet forward so that they are at 90 degrees.

Clasp your hands together and hold your hands out in front of you with your arms straight pointing to the ceiling.

Roll towards the right and then to the left. This is one repetition.

Do 12-15 reps. You can increase the difficulty by holding a free weight disc or kettle weight.

So there you have it. The five alternative abs exercises that strengthen core muscles and help you towards flattening your stomach. You can with these exercises use them in a flat abs program and perform them instead where you are instructed to do a set of ab crunches. So if you find abs crunches boring or you just want more variety then these new abs exercises are just what you need!