G’day Tom
I don’t have a problem with it. Its like doing sprints with a sled followed by normal sprints – you feel faster because you don’t have the load attached anymore. It can also work if you are just working on the shrug before putting it to the full movement. I tend to perform more powerful exercises first but rugby is a hybrid game where you have to be powerful under fatigue. So both methods work but for different reasons.
Cheers
Damian