someone should jump wear sack from the starting line towards the end of the track and return the original starting line. If done in a group game, when the player has returned to the starting line and he will be replaced by another player in the team. And, the team that made it to the start / finish in the fastest time is declared the winner.
For the record, the race typically use knockout as many number of participants. So, if a person or a team managed to win, he had to fight again another winner. While the losing disqualified and can’t play anymore.