 Complete the following phrase:  World Rugby announced in 2017 that it would add a major change to the laws governing the ruck among an ongoing series of global law trials. Under this trial law amendment, a ruck is formed when at least one player is on their feet and over the ball which is on the ground. At this moment, the offside lines are set. A player on his or her feet typically the tackler can use hands to pick up the ball if the action is immediate, but once an opposing player arrives at the ruck, no hands can be used. Additionally, kicking the ball out of a ruck is explicitly penalised, with only hooking in a backwards motion allowed. The trial was used for several international competitions in 2017, among them the 