A note about glute bridges:
While not hard, I for one was doing them incorrectly for a while. If you feel it in your hamstrings or lower back at all then you are doing it wrong. Mark Vestergen had a cue where you touch your glute with your hand at the top of the motion to ensure it's not "flabby."
"And for crying out loud. Don't go into the pain cave. I can't stress this enough. Your Totem Animal won't be in there to help you. You'll be on your own. The Pain Cave is for cowards.
Pain is your companion, don't go hide from it."