Partner Slap
A good sports specific exercise, especially for Basketball and American Football / Rugby players. Persons with good abdominal strength, looking at improving sports specific actions, should only perform this exercise.
Stand upright in a secure position, holding a small Swiss Ball close to your chest, whilst your partner will aims to slap the ball from a multitude of directions, forcing you to contract the muscles of your core stabilization to prevent excessive upper-body movement, and also the ball being released.
You can increase the difficulty level of this exercise, by performing with your eyes shut, so you have no idea of where the slap is going to come from, and hence prepare your muscles for the reaction required.
Foot position, a sturdy double shoulder width approach should be started, with progression going to feet together, then standing on single leg; and finally standing on either a Bosu or suitable wobble board.
Work for a desired amount of time, stopping prior to poor technique or discomfort set-in. Always communicate with your partner, they should aim to apply enough pressure to force your core stability muscles to contract and work - not enough to knock you totally off balance or send the ball flying out off your arms.
Avoid slapping the ball from underneath, or any direction that could send it into your partners face.