Athletes take to the water during the swimming competition at the Ironman 70.3 Kansas, the first of the competition's three legs, Sunday morning at Clinton Lake. An estimated 4,000 spectators cheered on more than 1,000 athletes.

Even after storms caused organizers of Sunday’s Ironman 70.3 Kansas to shorten the final leg of the triathlon shortly after 1 p.m., spectators kept a sideline vigil, urging participants on and keeping them motivated until the very end.

They lined the roads adjacent to the Ironman course at Bloomington Park, sitting in lawn chairs and cheering from trailer beds. An estimated 4,000 spectators were there to watch more than 1,000 athletes.

The triathlon may be an individual competition, but athletes said an enthusiastic crowd can be just as important as months of training. It’s one more reason to continue swimming, biking or running.

“It means everything. It really helps you get through it,” said Scott Bolen, of Overland Park. Cheers from friends and strangers alike help push the athletes through the pain of a triathlon, he said, and the crowd gathered by the shores of Clinton Lake held up their end of the bargain.

Spectators at Bloomington Park seemed to understand their role in the competition. Karen Douglas, who came from Omaha to support her husband, Michael, was ringing a cowbell nonstop. But she knew that her cowbell was helping more than just her husband.

“I’ve been ringing for five and a half hours,” she said at noon, pointing out the growing calluses on her hands.

She said she wanted to show her appreciation for the athletes, some of whom were participating to benefit a charity. “They’re testing their limits, and that is really inspiring.”

Brenda DeGroot, of Lenexa, said she can tell by looking at runners’ faces how much the support of total strangers means.

A smile here or a thumbs-up there was all the response some athletes could muster, but DeGroot said she knew her efforts were appreciated.

“They’re dying, and they’re telling me thanks,” she said, as she and several friends shouted encouragement to participants completing the final stage of the triathlon, the half marathon.

Sean Byrne, 20, came to the Lawrence competition from the Cleveland suburb of Rocky River to train for another triathlon in Michigan. Byrne, who has completed several marathons, said he learned that his body reacts differently in a triathlon.

And though he was pleased to complete the race with his parents, Dana and Rita, watching, it wasn’t the athletes or the personal accomplishment that impressed him the most.

No, it was the hundreds of clapping and cheering spectators.

“I think that’s one of the best parts,” he said.

“The excitement’s contagious,” said Dana Byrne.