Fantastic. I think the upright pose you illustrated is probable for feeding and confrontation. I expect them to have leaned forward a bit more (but still quite upright) when they were going somewhere that took more than a couple of steps, as walking would be more efficient that way.
Thanks! I'll refine this according to your feedback and prepare a more fleshed-out reconstruction. I also speculated about t.saurs spending most of their time on their backsides, shuffling about baby-style ([link]) and getting up only to walk and run, but that might have been unlikely.
Interesting. I wonder how it would look walking in that pose though. Would bending the knee even further cause problems?
The feathers remind me of something I was wondering about a day ago: did therizinosaur have the kind of complex protofeathers that could be green in colour due to structural color, or were they restricted to melanins?
This idea grows more and more on me as I study theizinosaur and bird skeletons, but I have no professional conclusions. Perhaps therizinosaurs sat most of the time on their haunches, and moved forward in a weird "baby-butt-shuffle" mode, [link] (like this movie,) with wing-like flaps of their arms helping them shuffle forward. They could do a plodding walk or move Greg-Paul style as juveniles, or when they really had to run.
I'm not sure about the green color - it was speculative. Most likely they were dark brown or black, covered with feathers - or spikes or pongolin-type scutes?