Analyzing Today's "Failed" Tempo Run

The image illustrates the pace for today's run. The slow sections of approximately 1.5 miles at the beginning and end of the run are the warm-up and cool-down. The faster-paced sections represent the 4-mile tempo run broken into quarter mile increments. My target pace today was 6:32 per mile. As you can see, I faded - getting progressively slower then scrambled to "stay fast" and "save the run" as I approached the end of the tempo. This isn't how a tempo is supposed to be executed. Ideally, the pace is constant throughout. My target pace today approximates my threshold pace which shouldn't be easy for me. It's also a high wire act to stay at that pace. The risk of going faster is that I'll end up going anaerobic and won't be able to recover. Thereby, dragging my pace and endurance down such that I slow down markedly. However, the threshold pace is a stretch that almost puts me at that point anyway. It's a huge challenge to hold on to the pace because I'm generally feeling like "Man, I can't sustain this. I've got to slow down!" It's all very strange. I believe the purpose of this workout is to put myself on the precipice and hold it there for what seems like eternity. This should build my fatigue resistance in the long run.

Remember, I'm not a scientist but I sure don't mind playing one ... on my blog ....