A backboard shattering (also known as backboard breaking or backboard smash) is an accident or stunt in basketball. It occurs when a player performs a slam dunk with sufficient force to shatter or otherwise destroy the tempered glass of the backboard, often causing the hoop to break off as well. Games are usually canceled or delayed and it incurs a foul for the offending player and costs of cleanup and replacement. Shattering a backboard can be dangerous, sending various small pieces of the backboard glass flying, potentially injuring players, sideline press personnel, referees, or spectators. In the National Basketball Association (NBA), shattering a backboard during a game is penalized with a "non-unsportsmanlike" technical foul and a possible fine towards the player. The player may not be ejected, nor shall the foul count towards a player's total towards either ejection or suspension. The referee also has latitude to waive off the foul, if it is determined the shattering was accidental due to a defect in the backboard or its structure, the board was broken during a rebound of the ball from a jump shot, or if the player had no intentions to dunk with force.
Throughout the history of basketball there have always been athletes with the size and strength to slam dunk the ball through the rim. However, the first recorded NBA player to shatter a backboard, Chuck Connors (who would become far more famous as an actor), did not do so with a dunk. When playing for the Boston Celtics in 1946, Connors took a set shot during pregame warmups, hitting the front of the rim. Because an arena worker had failed to place a protective piece between the rim and backboard, the backboard shattered. All-star power forward Gus Johnson of the Baltimore Bullets became famous as a backboard breaker in the NBA, shattering three during his career in the 1960s and early 1970s. In the American Basketball Association (ABA), Charlie Hentz shattered two backboards in the same game on November 6, 1970, resulting in the game being canceled. An invention by Arthur Ehrat to create the breakaway rim with a spring on it led to the return of the dunk in college basketball.