400m (or 400m Dash) is an Athletics event in both versions of the game, Mario & Sonic at the Olympic Games and can be found in the "Track" section of the "Athletics" category. The goal of the event, is to reach the finish line first. The smaller version of this event is 100m.
Racers will begin the race at their respective starting line. When the announcer announces On Your Marks and Get Set pressing on the Wii-mote will cause the characters to ready themselves and build up for a Start Dash. Once Go appears on the screen, releasing and swinging down the wii remote will give the player a boost. Running is controlled by alternating the movement of the wii-mote and Nunchuk (or just the Wii Remote if not using the nunchuk). Pacing oneself is the key to this event. A gauge appears above the controlled character and when racers begin to sprint (the speed meter is full and characters gain a bluish glow) their stamina begins to drain. If characters' stamina are depleted, they will slow to a walk until their meter replenishes. At the last 100 meter (straightaway) the participants will sprint their way to the finish line.
The event properties are the same in the DS version. The start dash however is performed by touching the touch screen with the Stylus and then releasing it when the gunshot is heard. Running is controlled by rubbing the stylus across the touch screen. The speed of the runner is determined by how fast the stylus is swiped across the screen.
Luigi's fourth mission in the Wii version is 400m. Luigi must beat all his competitors while staggering across the finish line.
Princess Peach's fourth mission in the Wii version is both 400m and the same as Luigi's fourth mission in the Wii version. To win, she must cross the finish line first. Once again, she must stagger across the finish line.
Dr. Eggman's second mission in the DS version is 400m. In this mission, Dr. Eggman must come in first, but he must avoid staggering.
Bowser's third mission in the DS version is 400m. He must win the race. Bowser loses one second as a handicap at the very beginning of the challenge.
Wii version: From a staggered start, kick off from the starting blocks, then endure a 400 meter run to the finishing line. The final 100 meter stretch should be sprinted to get you ahead of the competition, but take it slower at the start to avoid wearing yourself out.
DS Version: In the 400m, it is vital to pace your stylus control so your character does not over exert themselves and lose speed.