__By Ron Kaspriske
There's a widely believed theory—known as the principle of least effort—and it might explain why so many people struggle to make good golf swings. The theory suggests, in part, that people instinctively choose the path of least effort when performing any activity. You don't zigzag from your car to the front door. You walk on the shortest path possible. And when you swing a one-pound golf club, your instinct is to use only your arms because that's all the effort you need.
Unfortunately, to swing a club properly, you need to move more than just your arms. The bigger muscles of your body have to be involved, too, so Golf Digest fitness advisor Ben Shear (@[benshear](https://twitter.com/BenShear))) recommends tossing a medicine ball against a wall as part of your workout. Because med balls are considerably heavier than your clubs, you need more muscle power to throw one than your arms can provide—especially if you're trying to simulate the high-speed rotary action of the body that occurs during a golf swing.
"Your brain recognizes the increase in weight of the med ball, and it instinctively changes your neuromuscular recruitment pattern to let you throw it," Shear says.
Training with a med ball will especially improve your downswing, he says. That's when the leg, hip, and core muscles are already firing before the arms start to pull the club toward the ball. A similar series of coordinated muscle activity happens when throwing a med ball. When you're ready to give it a try, follow Shear's here:
__TRAIN TO CORRECT FAULTS
__If you sway or slide laterally during your golf swing, face a wall, grab a medicine ball with both hands, hold it by your hip and throw it against the wall in a golf-swing motion. "It'll help you rotate athletically during the swing without losing your balance," says trainer Ben Shear. If you tend to swing off your back foot, stand perpendicular to the wall when you throw the ball. "This will train you to shift your weight from your back foot onto your front foot at the top of the swing," Shear says.
SPEED IS KING
Working in slow motion won't train you for the quick muscle activity required in the downswing. "The faster you can throw it, the more you'll feel how the body should move," Shear says.
THROW BOTH WAYS
Toss the ball right-handed and left-handed to correct muscular asymmetry. "It's a big issue for golfers," Shear says.
USE A HEAVY BALL
The weight of the ball should be enough that you need more than just arm strength to throw it, Shear says. For a man of average strength, start with an eight-pound ball.
Ron Kaspriske is the fitness editor of Golf Digest.
(Photo by Dom Furore)