Just finished Spanish Needle -3 (the new version of build) and after 55ish microbursts I was pretty sure I was going to have to shut it down. I stood up and was able to plug on. I did the first two or three intervals of the remaining sets seated before standing again. I am glad I finished the workout rather than shutting it down and “failing”.
I am mostly a mountain biker so standing up is not a deadly sin in the grand scheme of things, but I wonder if I am missing the proper training stress by standing for these rather than staying seated and turning it down.