People who exercise and personal trainers tend to go overboard on certain exercises gettign too "cute" sometimes.
Make sure you master the basics before attempting exercises such as this one.
Learn about Exercise Balls
http://AskTheTrainer.com/best-exercise-ball.html
BOSU BALL EXERCISES
http://AskTheTrainer.com/bosu-ball-exercises.html
Stability Ball Exercises
http://AskTheTrainer.com/stability-ball-exercises.html
