The Science of the Summer Olympics

　　

　　The games are (finally) underway in Tokyo, and for the next two weeks, we'll witness the greatest display of sport physics at work.

　　After a year-long delay (and what a year it was!), the Tokyo Olympics are here finally here. For two weeks, the world's best athletes will put on incredible displays or skill, fortitude, stamina, and physics. Yes, physics.

　　To be the very best, athletes break down their sport to a science. Momentum is translated to joules, runners understand the intricacies of different muscle fibers, kayakers deftly navigate the math behind fluid dynamics. Here we break down some of the interesting science that'll be on display in the next two weeks.

　　Much has been written about the superhuman athletic ability of swimmer Michael Phelps. He’s a genetic wonder, built like a fish, with hands and feet like canoe paddles. All this is true—it is impossible to win at the Olympics without a genetic predisposition to your sport. Team USA at the Tokyo 2020 Olympic Games will be hoping to surpass—or at the very least imitate—what made Phelps a swimming phenomenon.

　　Body: Phelps’s body is a famously specialized swimming machine. His wingspan, at 6 ft. 7 in., is 3 in. longer than his height. And his long torso and relatively short legs—he has an inseam of 32 in.—let him ride high in the water.

　　Biochemistry: Strokes such as the butterfly tend to build up lactic acid in muscles, reducing their ability to perform. Phelps’s exact numbers are kept secret, but tests suggest that he naturally produces far less lactate than most athletes do.

　　Flexibility: Some sports require strength (shot put); others, flexibility (gymnastics). Swimming requires both. Phelps’s flexible elbows, knees, and ankles allow him to move through water with minimal resistance.

　　Hydrodynamics: In a 200-meter freestyle race, a swimmer moving at 3.8 mph expends 290 kilojoules fighting his own drag. To combat this, Phelps adopted a streamlined swimming posture—head down, hips high.

　　Technique: Phelps was the master of the dolphin kick. By pushing off the wall and whipping his legs, he can swim faster than with a traditional stroke—gaining an advantage of half a body length over competing swimmers.

　　Training: Phelps trained every day of the year—4 hours in the pool, 1 hour on dry land. Since swimmers can burn about 1,000 calories per hour, Phelps’s diet tended to be relatively high in carbohydrates to avoid glycogen depletion.

　　At the 2008 Beijing games, Michael Phelps was in a dead heat with Serbian Milorad Čavić. Čavić appeared to touch the wall first, but Phelps was the first to exert the 6.6 pounds of pressure required to activate the touchpad. The result: a victory margin for Phelps of 0.01 second, which the Serbian team disputed. But a review down to 0.0001 second confirmed Phelps’s gold.