Phelps caught napping at Columbus Grand Prix

By Steve Keating

COLUMBUS, Ohio (Reuters) - A brutal training regime caught up with Michael Phelps at the Columbus Grand Prix on Saturday when the American pulled out of the 400 metres freestyle after falling asleep on the diving tower.

"I was sitting over there on the tower and I fell asleep," Phelps told reporters. "(Coach) John (Urbanchek) and I decided just to swim the 400IM, get a good rest for the 400IM tonight.

"John came up and woke me up and said, 'We're going to trash the freestyle'. I was like 'uh', I was half awake."

Exhausted from an intense training schedule, Phelps, who won six gold medals at the 2004 Athens Olympics, has laboured at the Columbus meeting, saying he felt like a brick in the water.

The 22-year-old American had planned to test himself in six events over the three-day meeting but after swimming in three finals in 52 minutes on Friday will limit himself to the 400 individual medley on Saturday and the 100m free on Sunday.

Phelps, who plans to challenge Mark Spitz's record of seven Olympic gold medals at a single Games in Beijing in August, was fully awake for the 400IM, clocking the second best preliminary time of four minutes 21.89 seconds to set up a showdown with friend and training partner Erik Vendt in the evening final.

Katie Hoff has dominated the women's events here, picking up a pair of wins and clocking a personal best time of 59.45 in the 100m butterfly preliminaries.

After victories in the 100m butterfly and 800m freestyle on Friday, Hoff looks sure to add to her haul after posting the top time of 4:40.06 in 400IM qualifying on Saturday, touching more than eight seconds ahead of her nearest challenger Mari Embertson.