The only thing less likely than Bolivia medalling at the 2016 Olympic Games is anyone adding to the athlete mortality rate. Through 2010, only a handful of competitors have expired during or immediately prior to the Games, usually as a result of collisions, heart trouble, or sunstroke.

So why has Rio insisted on stationing lifeguards to watch over some of the most capable swimmers in the world?

According to Ricardo Prado, the Olympic sports manager for aquatics, the Games are simply following the laws set by their host country. “It is a Brazilian law that any public pool over a certain size has to have lifeguards ...” Prado told Reuters. “We have to have them.”

Rio mandates that any pool measuring more than six by six meters (about 20 by 20 feet) be monitored by a rescue professional. The city has assigned a total of 75 lifeguards across the events, including swimming, water polo, and diving. For 20 days of relatively stress-free work, the guards will be paid approximately $340.

Although it’s unlikely Michael Phelps is going to suddenly forget how to swim, it's not typically the freestyle or butterfly that's going to be of any concern: Synchronized swimmers have been known to collide and suffer concussions. In 2008, a participant in Beijing appeared to faint after completing her routine and had to be carried out of the pool.

[h/t The Huffington Post]