Silly answer aside, did you rest/taper for your race. What duration anaerobic intervals are you talking about, and are you as rested when you do them as you were for the race?
Using the "TT" method I had figured my LT was in the mid 170s but I did a test (using gas exchange not blood lactate) it came out in the mid 160s. For longer steady intervals or really intense shorter efforts I will go above that.
It is quite possible that you are just training "lazy" and quitting when it starts to feel difficult instead of pushing through like you may have done in the race. A lot of training is getting accustomed to the "suffering". Also you may just need to use an easier gear.