In American Football the ball is in play only about 15 minutes a game, so saying each game is 60 minutes long is not quite accurate.
At least in basketball ( NBA ) the players actually play for 48 minutes. Every second counts. When they are standing around waiting for a free throw to be shot for example, the clock is off.
Basketball games are shorter than other major sports, but the players are in a lot better shape than players in the other sports. If the clock is on, there is very little standing around in the NBA.