They are both basically a one-legged squats in effect.   You will feel it in the leg that stays on the step - with the back leg you are just trying to reach backwards (or sideways in the second one) - doing nothing more than making your other leg work to pull it back.   No pushing off, just a toe touch with that leg, while the other carries the load.

 

If I have to make a video, worlds may implode.

 

But seriously, I have never felt a burn in my tuckus like I have with this exercise lol

Add a bicep curl at the top of that block and that would be something I did this morning.  I go to a workout class a couple times a week and mentioned that I needed to work on hip and glute stuff (I got that from that book!), so she always works something in for me.

I couldn't  really do a bicep curl with this one because to counter reaching backwards with the back leg, you have to lean forward with your arms.  Though maybe people with better balance could lol

I thought the second pic was a different exercise. I get it now, lol.