The single-arm DB press is a fabulous pressing variation for developing anti-rotational strength through the core. At the bottom of the DB press, the centre of mass is lateral to your torso creating a force that is trying to rotate you off the bench. Using your core and legs you have to work to resist this movement. This rotational force is dynamic as at the top of the lift you are pretty stable, so the core is working hard and reactively, what a great combination. If your client can do the normal DB press well you should be able to progress them to the single-arm version just start slow and build up as they may not have developed the torso strength and technique yet to stabilise this exercise.
Dave Stewart
The Trainer's Trainer
