There are many core exercises that you can do on an exercise ball.  The ball will make your abs, lower back and core muscles work much harder because the ball is unstable.
 
Crunches on the ball are a great exercsie for beginners to master and you can learn that exercise plus 7 more great core exercises on my exercise ball core workout video.
 

If you're into core training chances are you're doing tons of abdominal exercises, but it is just as important to focus on lower back exercises.
The lower back muscles compliment the abdominals to keep the spine stable.
Click here to watch a free video explaining the benefits of core training.

Doing exercises on the ball, can increase core stability.  Doing the chest press on the ball increases your core stability, shoulder stability, and hip stability.
 
To further increase the challenge to your stability you can do the alternating chest press or the 1 arm chest press.
 

Did you know that you can easily turn arm exercsies and leg exercises into core exercises?
You can use a simple upper body core training stability progression to turn arm exercises into core exercises.
And you can use a simple lower body core training stability progression to turn leg exercises into core exercises.

If you are looking to change up your abdominal workout, try this exercise that works multiple planes of motion!
The side plank crunch provides you with more than just a core workout.  You will engage so many more muscles than the standard crunch, it will bring your fitness to a different level.
 Go to www.exercise-training.com/sideplank.html

I've been trying to pay more attention to my core, and today I used 2 Bosu Balls for planks and side planks.

I did 2 sets of moving side planks with both my hand and my feet on Bosu Balls.  You can check out the exercise at ab-core-and-stomach-exercises.com

The Stability ball can be used in so many ways to increase your core strength.  In addition to crunches and piques, you can also do many different plank variations using the stability ball.
 
Try this hard core exercise on the stability ball: plank forward rolls or try plank side to side rolls on the stability ball.
 

The plank and its many variations are best abdominal exercises for women and men.  Combine the plank with a stability ball and you've got the makings of a great core workout.
 
Try 1 leg planks with the hands on a stability ball or try them with the feet on a stability ball.
 

The Stability Ball and the Bosu Ball are great tools for core exercises, and when you combine planks and knee ins on either ball you can get a great core workout.


Try knee ins on the stability ball.
 
Or try knee ins on the bosu ball.
 

The Bosu Ball is a great tool for core exercises, and one of the most effective Bosu Ball exercises for the obliques is side planks with the elbow on the Bosu Ball.
 
All the best oblique exercises utilized side bending motions or rotational motions, and when you combine side bending and rotation with a Bosu Ball you can get a great oblique workout.