Football Restraining Line
The restraining line in football is an imaginary line that players are not allowed to cross during kickoffs until after the ball is kicked. The restraining line is often used to align the players of each team. The line runs parallel to the sideline. The kicking team's restraining line is on the 35-yard line close to their end zone while the receiving team's restraining line is placed ten yards away on the 45-yard line. Both restraining lines are on the kicking team's side of the field.
One of the main purposes of the restraining line is to differentiate the active players from the inactive ones.
The restraining line also prevents the receiving team from blocking the kickoff. If they were able to get right up to the kickoff line, it'd be impossible for the kicker to propel the ball over the receiving team's players.
Restraining Line on Onside Kicks
The restraining line is the same for onside kicks, which makes recovering onside kicks difficult for the kicking team as they cannot recover the ball unless the ball travels at least 10 yards. They must send the ball into the sea of defensive players and hope for a good bounce.
What if a Player Passes the Restraining Line?
If an inactive player stands too close to the action, they will be asked to move. If an active player stands over their restraining line, they could receive a flag which would affect the spot of the ball after the kick.