Triathlons are tough, even for the people who run in them all the time.

Case in point: Jonny Brownlee. On Sept. 18, Jonny was running the final race of the World Triathlon Series in Cozumel, Mexico, and doing quite well until the final kilometer of the race. The heat in Cozumel was taking its toll, and Jonny began to wobble and weave. Just as it seemed Jonny would collapse near the stands, around the corner comes another runner — his brother. Alistair wrapped his arm around his brother's shoulder and led him to the finish line, pushing him over the line to finish in second place behind South African Henri Schoeman. (Schoeman celebrated his wins with high fives and fist pumps, but we wondered who the crowd was really cheering for.)

The sacrifice was no huge loss for Alistair. Due to missing a few races in the series, he was out of contention for winning the series. Jonny, however, needed to win the race to place first in the series. Spaniard Mario Mola, who placed fifth in the Sunday race, won the series overall, remarking, "[W]hen I heard Jonny isn't [sic] feeling well, I thought 'I need to fight to the end.' We want everyone to be safe after the finish line, it's not the way I wanted it, but that's triathlon."

An appeal was made to the International Triathlon Union to disqualify Jonny over getting assistance of his brother, but the rules allow racers to offer and accept help. In fact, Alistair himself had a similar scare in a 2010 race, and after that, he decided he would help anyone — brother or not — if they needed it. As he told the BBC, "If he'd conked out before the finish line and there wasn't medical support, it could have been really dangerous. It was a natural human reaction to my brother, but for anyone I would have done the same thing. I think it's as close to death as you can be in sport."

Jonny collapsed thanked his brother from his hospital bed with a tweet: