MN/PE1>iM substitition needed

What can I do for my shoulder as a substitution for this iM while I'm nursing a hamstring issue?   

The same, just seated (?) - not exactly the same when body is bit more fixed though, but close, chair on wheels will help a bit , Xiaopengs maybe.

Thanks for the suggestion.  I'm going to try it on the seat.    I'm just going to have to work on tuck up form and then restart the whole cycle with the iM whenever I get the leg in good order.         I just don't want to stop the entire element in the meanwhile.