Pull tired players from the game. Fatigue is a common cause of injury during intense games. To prevent injury, take players out of the game when they're tired. Help players avoid fatigue by stressing proper conditioning before and during the season. Look for signs of injury.
Some injuries are easy to spot.
Very often, the injury will not be obvious, or the young athlete won't tell you that he or she is hurt. Watch the player's body language. Injured players often limp, wince, favor one limb over another or try to compensate for a weakened or sore limb. If you suspect an injury, pull the athlete from play until he or she can be evaluated by a medical professional.