Finals: Aug. 5 (women), Aug. 8 (men).
How it works: Six or fewer riders start from a standstill, either held by helpers or holding onto the edge of the velodrome. Once off, the riders queue up behind an electric motorbike, and they are arranged in an order decided by drawing lots prior to the event. The motorbike brings the riders up to speed over the course of three laps, hitting the rate of 50kph. Then, the pacer pulls off, letting the riders battle it out over the final three laps, with the first rider across the line winning.
At the Olympics 30 riders start, and the first two riders across the line in the opening round advance to the next round. Four riders advance in the second round, with the third round determining which riders will race for the medals.
What to watch for: Positioning in the lineup is of utmost importance in the Keirin, so look closely at the riders as they accelerate after the motorbike pulls away to see them bumping and jostling for the best placement. Once the motorbike pulls off there will usually be one rider who tries to surprise the bunch, while the more experienced sprinters will often wait for the final push to the line. Keep an eye on which sprinters have the patience and nerve to wait until the last possible moment to accelerate.
Favorites men: Harrie Lavreysen (The Netherlands), Jason Kenny (Great Britain), Azizulhasni Awang (Malaysia)
Favorites women: Lee Wai Sze (Hong Kong), Kaarle McCulloch (Australia), Emma Hinze (Germany)
North Americans: Lauriane Genest, Kelsey Mitchell, Hugo Barrette, Nick Wammes (Canada), Maddie Godby (USA)