Prerequisites - how's my form?

Can I get some critique on my form for the prerequsites guys? I've started again. Specifically for the following:

Plank,

Rev Plank,

Arch Hold

Hollow Hold

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Thank you

Decent.

Hollow hold has the feet a bit high for my tastes but I generally teach the hollow hold with the arms down at sides, then progressing to vertical and behind the head over time.

I might want a little more shoulder curl and to check to see if there is any space underneath your lower back.

I think your reverse plank could use a big more t-spine extension. Try to push the chest up

Thanks Blairbob! I have a bit of a problem with the hollow hold. I can't get proper positioning. Where am I supposed to rest? At times, I can rest on the lower back fine but more often than not, I end up supporting myself around my sacrum to the coccyx bone ?

Thanks Phrak. I tried pushing my chest up just now - got a case of early parkinsons immediately. Awesome!

Lower back.

I like your music choice.