Back in 2014, we put Dustin Johnson's girlfriend, Paulina Gretzky (left), through the paces of a golf workout including use of one of the most beneficial pieces of equipment in any gym—a physio ball. There are literally dozens of exercises you can do with one, and Golf Digest fitness advisor Ben Shear and I demonstrate a few of them below. Physio balls cost $20-$40 and come in various sizes. Typically men should use a 75mm ball while women would be better off using a 65mm or 55mm ball. It's smart to check this out before buying.
Why is a physio ball so useful? In a word: Instability. In order to perform most exercises with a ball, your body has to make up for the lack of stability that the spongy, round ball doesn't have. So you have to use several muscle groups—most notably the core muscles around your midsection—in order to avoid falling off the ball. This "stability-first" mandate is similar to what needs to happen in order for you to swing a golf club effectively and safely. Without bracing yourself, you can't swing a golf club without losing your balance.
The plank that Paulina is demonstrating here is just one of many exercises all golfers should incorporate into their routines. This one is especially good if you move the ball around with your forearms rather than just staying still. You'll really feel it working your core muscles. For other great physio-ball exercises, click on the videos below.