You're probably aware that there's a "Hard Edge" message painted inside the Michigan Stadium tunnel just before the "Go Blue" message.
It looks like RichRod (or his designated Twitterer) is looking for some of that spirit as practice begins:
UM_CoachRod Getting geared up for practice #1....Hope to see a lot of Hard Edge
Here we go...
[Edit: This post is targeted at anyone who finds it interesting that RichRod (or one of his subordinates - maybe even the new Director of Football Operations (does he work for RichRod?)) sent out a Tweet (pretty rare event) using a saying that appears inside the Michigan Stadium tunnel and is known to most diehard fans but is probably not universally associated with Michigan football potentially signaling a coach's emphasis during the pre-season camp on this concept (but certainly not Other Chris).]