SLIPPERY ROCK — Jenna Rinker has a secret weapon on the golf course this summer.

It's not a new club. It's not a newly refined swing.

It's in her core — literally.

The soon-to-be 16-year-old from Slippery Rock has dominated the junior girls golf circuit, winning three tournaments and placing second in two others.

She's done it with an approach rarely seen for a golfer her age: pumping iron.

"It's all about golf," Rinker said. "It's a lot of core work — abs, stability, building the core muscles. The golf swing mostly comes from the core."

Her added strength has helped Rinker shave nine strokes off her score since last summer.

She's also added distance to her drives, which now scream off the tee and travel between 200 and 215 yards.

"Lifting weights makes a huge difference," Rinker said. "Golf is a power game now. Look at Tiger Woods. He lifts and look how great he is."

Rinker speaks with a knowledge of the game that belies her youth.

She didn't start golfing competitively until two years ago, but she immersed herself in the nuances of the game and quickly improved.

Rinker still is in awe of how far she has come in such a short period of time.

"I think about it all the time," she said. "I think, 'Wow. How did I do this?'"

In addition to her weightlifting routine, Rinker also has improved the old fashioned way.

She spends up to four hours a day at the golf course, chipping, putting and working out the kinks in her game.

When she's not practicing, she's playing in tournaments. Rinker enters an average of three events a week.

That's a lot of golf. It's still not enough for Rinker.

"I love it," she said. "I can never get sick of it."

Golf has consumed her so much that she is giving up her other sport, basketball, to hit the links full time.

Her goal is to play golf in college — and not just any college.

"I want to go somewhere south so I can play year-round," Rinker said.

Rinker has very few holes in her game right now. She is shooting in the low 80s, down from the 90 she routinely fired last summer.

Her success has her hungry for more.

"I remember last summer I was happy to shoot a 90," Rinker said. "This summer, I'm pretty bummed if I shoot a score like that. It's so amazing how my standards have changed so quickly. I want to get down into the mid-70s. I have to keep getting my scores lower."

Driving the ball farther has helped. So has her improved short game.

A golf tip from Rinker: "When you are practicing your chipping and putting, you definitely have to vary the distances. You're not going to get the same chip every time."

Rinker's next event is Tuesday — her 16th birthday — at a King's Family Junior Golf Tournament event at Oak Tree Country Club in West Middlesex.

She's hoping her round makes her 16th birthday sweet.

"I'm really playing well right now," Rinker said. "I really couldn't pick anything out in my game that I'm not happy with. I'm pretty consistent right now. It's a really great feeling to be able to say that."