The Runner Shoes, also known as "white shoes", are one of the three pairs of special shoes available in the coin shop for 400 coins and also in the marketplace.
The Runner Shoes gives the player the ability to adjust the run speed of his/her character while in-game. Walking all the way to the left slows the player down while walking right speeds it up. This can be helpful in multiplayer if the player wants to create some distance between him/herself and the rest of the competitors. It also gives the player and edge later in the game when the overall speed has dramatically increased.