56.6 Only one player from each team may make an attempt to gain possession of the
ball. Any other player that accompanies the player attempting for the ball must
not be within a radius of three (3) metres from the body of the player attempting
for the ball. Infringement incurs a free throw.
This rule needs a bit more elaboration/interpretation. I assume the 3 metres is body to body distance, but when does the initial sprint "attempt" start and finish? Does the sprinter have to have 3m clearance on each side of him/her at the goal line from the moment the start whistle is blown, and is it the line judges responsibility not ensure that this is so before indicating the team's readiness to start? When does the "attempt" by the sprinter finish, thus enabling another player to come within 3 metres? Perhaps it should be when either or both sprinters take possession as defined in rule 64.1 (A player is in possession of the ball when they have the ball in their hand or are in a position to reach the ball with their hand).