The league rule book says, "A personal foul is illegal physical contact which occurs with an opponent after the ball has become live."
For example, in basketball, a personal foul involves illegal personal contact with an opponent.
Charging is defined as illegal contact by pushing or moving into another player's torso.
Blocking is illegal contact which impedes the progress of an opponent.
There was a 5-yard penalty for illegal contact that gave the Bills an automatic first down instead of third-and-8.
Scoring increased as penalties for illegal contact rose drastically.
Any illegal contact between players will result in a free throw.
The basic approach is to mask the illegal contact with expected, benign contact.
Charge - A violation in which one player makes illegal contact with another player who has an established position.
But any sport has risks and those associated with illegal contact are still part of the sport.