It wasn't that long ago when golfers were told to avoid lifting weights for fear of destroying their swing. While the image of a muscled-up golfer isn't exactly what you're used to seeing on the links, any golfer or enthusiast worth his putter is engaged in some form of resistance training.

"I'd say 95% of guys on tour my age and younger all lift weights," says Ricky Barnes, a 31-year-old player who's developed a reputation for being one of the fittest veterans on the PGA Tour. "And for every five years you go up in age, you probably would see a 10% decline in the number of guys lifting."

Barnes lifts six to seven times a week during the off-season, and two to three times per week in season.

While he doesn't avoid upper-body training, he says his primary focus is strengthening his legs and core.

"In the off-season, you're trying to get strong but maintain flexibility so you can still take a good thrash at the ball," Barnes says. "It's a delicate balance, but it can be done."

While the in-season workouts might not seem overly daunting, those sessions are just as crucial to his success in a long competitive season on the PGA Tour.

"We play 16 competitive rounds in four weeks, and 22 total rounds when you factor in practice," Barnes says. "That takes a big toll on your body."

Barnes uses the following leg workout during the season to strengthen his swing while still maintaining flexibility. Perform three sets of each exercise and 15–20 reps per set.

Walking Lunges
Hold a pair of dumbbells at your sides and take long strides, landing on your heel and dropping your back knee to the ground.

Lying Hip Extensions
Lie supine with your right knee bent, your right foot flat on the floor, and your left leg extended. Drive your right heel into the ground and use your hamstring to extend your hips.

Banded Crab Walk
Loop an elastic band around your lower legs, just above the ankle. Take long, lateral strides to your left, controlling the tension of the band.