Building off the exercise I posted the other day, this is another dynamic movement that trains core control. The idea is that you minimize the rotation of your trunk while catching the ball. You can progress this exercise by having your partner throw the ball slightly further away from your shoulder. You could also make the throws back to your partner more explosive, but the exercise is designed to teach core control and anti-rotation, not explosive power. There are plenty of other exercises for that!
Kevin Neeld