Some of you guys post that you do 2x20' intervals at 90% or 95% with a lot of regularity. I've found that I have huge swings in my ability to complete these types of efforts and want some feedback about what would be considered 'normal'.

For the last 1.5 weeks I've been trying to get some threshold work done, but every time I try, I fail my efforts. I've lowered the bar each time to try and titrate out what I can complete. Then today, out of nowhere, something clicked and I hit some huge threshold intervals.

So anyways, feedback?