Want to catch a glimpse of athletes jumping in a lake, kicking each other in the head, peeling off clothes, speeding away on bikes and then running back to the point they started from at least four hours earlier?

Set your alarm.

Spectators for the Ironman 70.3 Kansas are encouraged to be at Bloomington Beach at Clinton Lake by 6:15 a.m. Sunday, in time for the opening of ceremonies and the 6:45 a.m. start of the grueling race that begins with a 1.2-mile swim, turns into a 56-mile bike and finishes with a 13.1-mile run.

Not that the fans have to worry about such tests of endurance.

“Get there early, and just plan for a day at the beach,” said Ryan Robinson, co-director for the Ironman event, a first for Kansas. “That’s pretty much what it entails, except that there’s a sporting event going on.

“Come on out, bring a lawn chair and a cooler and make a day of it.”

Some 1,500 athletes – from world-class professionals to aspiring weekend warriors – will compete in the triathlon, covering half the distance of a full-length Ironman event.

The festivities actually start Friday, with the Event Expo at Ninth and New Hampshire streets downtown. The Expo runs from 2 p.m. to 8 p.m. Friday, with competitors able to pick up their packets and other course information. Navy SEALs will have their Accelerator course and simulator set up for interactive activities, and more than a dozen vendors will be showing off their triathlon-oriented products and services.

A free, live concert – dubbed “Lawrence Live!” – starts at 5 p.m. Friday with Apollo 13, followed by Garrett Nordstrom Situation at 6:30 p.m. and Poi Dog Pondering at 8:30 p.m.

Saturday events, also at Ninth and New Hampshire, include the Adidas Rock Chalk Run (5K and 10K) at 8 a.m., and the Expo from 10 a.m. to 2 p.m., which includes the SEALs Accelerator.

“It’s a great summer event,” said Bob Sanner, sports director for the Lawrence Convention and Visitors Bureau, an organizer of the Expo.

And that, he said, includes the race itself, set to begin bright and early Sunday morning.