4x100m Relay

From the Super Mario Wiki

The 4x100m Relay, prounounced 4 by 100 Meter Relay, is an Athletics event (specifically, Track) in the Wii version of Mario & Sonic at the Olympic Games. The game is a four-character relay race, which starts with the character the player picks. In Circuit mode, the additional characters are chosen at random. In Single Match mode, the player may pick the extra three characters in addition to their standard character.

The team switches every 100 meters by passing a baton. When a character's speed is locked, they can begin the next character's run by pressing B and hold the baton out to pass by pointing the Wii Remote frontwards. If the timing is bad, the switch will be slow and bad. But if the timing is just right, the person who takes the baton will be boosted.