Escape - The Yard
Near the beginning of the game, you'll take control of the characters in the prison yard. You'll want to take control of Leo and talk to an in-mate near the some vertical bars workout equipment. He'll tell you that the record amount is 20. Now, as Leo, interact with the vertical bars and mash the X button. Once you reach 20, you'll be interrupted with dialogue letting you know that you set the new record, and the achievement will unlock for both players.
This achievement can be seen in the video guide at 0:03:NOTE:
Achievements are only available to owners of the game. Players using the "Free Trial" friend pass will NOT unlock achievements.