The most effective Abs Workouts!

Everyone want to have a  Strong core for good exercise performance  but how to do this?

I think the most effective Abs Workouts is:

1.Bicycle crunches.

Frist, You have to lie on your back with your lower back pressed on the floor, your knees have to in towards your chest & lift your shoulder blades off the floor. 

2. Lie on the balance ball

You have to lie on the balance ball with your hands behind head and complete the simple crunch, the main point is to use your core muscles to make yourself lower & bring forwards.