By Julian Linden

NEW YORK (Reuters) - Every day, Michael Phelps wakes before dawn, packs his swimming trunks, goggles and towel in his bag and heads to the pool.

Then, under the strict orders and careful observation of his long-time coach Bob Bowman, he plunges into the water and starts churning through the laps, slowly at first then building to ferocious speeds.

He trains again in the afternoon as part of an exhausting and punishing schedule with no rest days. By the end of the week he has clocked up nearly 70 km (43 miles) in the pool.

"And that's the fun part," said Phelps. "I actually enjoy training. I enjoy working out. I want to be there because I want to be better."

Better? At 26, the American is already the greatest swimmer the world has seen and a sporting immortal with 14 Olympic gold medals, including an unprecedented eight in Beijing.

But Phelps is not satisfied with what he has achieved. He might slice through the water as gracefully as a dolphin, but he still has all the predatory instincts of a killer shark.

"Every time I get into the pool, I want to race, I want to win," Phelps told Reuters in an exclusive interview marking the launch of his appointment as the global face of head&shoulders anti-dandruff shampoo.

"No one's forcing me to workout, no one's forcing me to go into competitions but I enjoy working hard because I still have goals to accomplish."

But just like he did before Beijing, Phelps will not say what his goals are for next year's London Olympics, saying only that he will not swim eight events, but his motivation is no less.

"I've been training a lot harder than I have been in the past few years and I've been able to see a lot of success," he said. "I kind of feel like the old me again, being able to swim fast again, at any given time.

"It's just good for me confidence-wise heading into these next few months to really just try to have one real, big last surge to be able to have the opportunity to try and accomplish my goals and dreams to finish out my career."

Since winning eight golds at Beijing, Phelps's form has dipped. He won five gold medals at the 2009 world championship in Rome then four in Shanghai this year and suffered some rare defeats that made him question his commitment.

He realized he was not working as hard as he should have been but rather than rest on his laurels he returned to training with renewed vigor and believes his best could still be yet to come at his fourth and final Olympics.

"There are a lot of swimmers in the world who are a lot faster than they were and are improving and I know it's going to take me at my absolute best to compete with them," he said.

"But they have given me motivation. I'm not going to give up. I still don't think I've reached my potential."

(Editing by Frank Pingue)