For the first time, Woods and trainer Keith Kleven offer detail and insight into a fitness regimen that has enabled the world's No. 1 player to add nearly 30 pounds of muscle since he left Stanford in 1996 after his sophomore year.
'Pound for pound, I put him with any athlete in the world,' Kleven told the magazine.
The routine is built around stretching up to 40 minutes before each session, core exercises, endurance runs of 7 miles and speed runs of 3 miles, along with weight training. But while Woods is competitive on the golf course, he said he doesn't have an ego in the weight room.
'I've never, ever hurt myself lifting,' Woods said. 'I hear people say, 'I hurt this' or 'I hurt that.' I don't even know what that feels like. I've been sore, but I've always been able to function and do whatever I wanted to. ... Some people let their ego get in the way. You have to listen to your inner self. Your body knows when it can be pushed and when you just need to back off a little bit.'
Woods opts for high repetitions and smaller weights, although Kleven said he is 'off the charts' with how much he can lift.
'His endurance and strength allows us to do more reps at high levels than normally seen in a golfer,' Kleven said, without disclosing specific weights. 'His resistance for high reps is extremely high.'
Woods is featured on the cover of Men's Fitness, which goes on sale Friday. He is wearing a red, sleeveless shirt and holding a golf club. The photos that accompany the story show Woods in the gym doing pull-ups, squats and curls.
Woods was wiry when he left Stanford, at 6-foot-2 and 158 pounds. He said he tried to gain weight through high school and college, but his father told him that family history suggested he would not be able to gain weight.
'Dad would say, 'You probably won't hit your optimal weight until you're 30 or 35,'' Woods said. 'I said, 'I'm trying to put on weight.' He said, 'It ain't gonna happen. When the body says it's time to fill out, it'll fill out.''
Woods said he continued to lift weights without seeing any results, and the change occurred about the time he won the career Grand Slam in 2000 at age 24.
'I was actually able to lay down muscle for the first time, and I was able to keep it,' Woods said. 'It was exciting. I'd never experienced that before. It was nice to feel stronger. All that work was starting to show up.'
Still, Kleven said their various routines are built around posture and balance.
Woods, who became a father June 18, has plenty of company in some of his workouts. He said wife Elin was doing 45 minutes of cardiovascular work when she was seven months' pregnant.
'She's a runner, just like I am,' Woods told the magazine. 'There's no doubt I'm faster than she is, but there's no doubt she can run a lot longer than I can. She can keep her pace up forever. It's frustrating because I like to go for speed, and she can go all day. If we were doing a half-marathon, she'd smoke me.'
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