First off, it wasn’t exactly a race. Phelps swam alone, time trial style, in the waters off South Africa.

It also wasn’t exactly a shark. When the “race” was shown, Phelps was matched with a computer-generated image of a shark, supposedly simulating a real shark’s speed. The “shark” even leapt out of the water at the finish line for a conveniently spectacular visual.

The show also faced the problem that sharks and people are not comparable swimmers. Not even close. Humans, even superhumans like Michael Phelps, swim no faster than 6 miles an hour. Great white sharks hit 25 m.p.h. Phelps was given a monofin, which let him swim faster than his world-record times. But he still wasn’t going to come anywhere near the shark’s top speed. This certainly seemed like a stumbling block for an interspecies race.

Earlier in the program, scientists lured a shark with a fake seal to time its speed over 100 meters in a straight line. Conveniently, the time they came up with was in the range of Phelps’s speed.

“I think we did our best to try to make it as close as we could,” Phelps acknowledged to Entertainment Weekly.