Synchronized Swimming (Duet)
From the Super Mario Wiki
Synchronized Swimming (Duet) is an Aquatics Event which appears exclusively in the Nintendo 3DS version of Mario & Sonic at the London 2012 Olympic Games. The objective of the event is to score the most points by performing various moves in the water in time to the music. The event has a starting world record of 92.1pt(s) but does not appear in the game's story mode.
For this event, the player must choose two characters from the Heroes category, and compete against a team of the other two heroes, as well as a pair of Chao and a pair of Koopa Troopas. To perform moves, the player must press the A Button at the same time as the two matching symbols overlap. Performing the move with perfect timing gives the player a higher point score and is indicated by the characters who performed the move having a rainbow sparkle. at various points in the event, the two symbols will swap sides, and the player must press left or right on the control pad to switch the sides of their cursor to be able to perform the move. Performing successful moves successively will cause the player to begin earning combos, which will result in a higher score. The maximum combo that can be obtained by performing all of the moves perfectly is 60. Performing the move with the cursors the wrong way around, pressing the button at the wrong time or failing to press the button at all will cause the player to fail the move and lose any combos they've built up.
1) Performance: Press the A Button at the right time.