Professional football players are the biggest, strongest and fastest athletes in the world. They’re paid millions of dollars to play a game that most people would give anything to be able to play for free. Professional football players are expected to perform at an extremely high level during every single game they play. They must have incredible endurance, speed, strength, agility and coordination. Stamina is the ability to sustain physical activity for long periods of time. Professional football players often perform for an entire game, which can last up to three hours. Stamina is important for maintaining a high level of performance throughout the game.