Running, todays workout

Running at treshold-pace tonight. My body is not stiff after the race last Saturday, but a I feel a bit worn out. The schedule for the rest of the week consists of cross-training and two long-runs.
Anyhow, some technicals:
-Treshold pace right now is: 4m 42s
-Average heart rate: 170 (right on target!)
-Body-weight(this morning): 75 kg
-Shoes: Mizuno Wave Ronin

A treshold-workout is difficult. It's easy to get trapped and start at a higher speed than the sustainable speed. It's important to set the speed I'm able to keep throughout the workout. To be even through the entire workout is important. In races a negative split is wanted. Tonight I started out a bit to high-about 3,75. I need to adjust that the next time. I finished at 5. The spread is 33 %. That is to much. Next time I'm starting at 5 and working my way down to 4,5. Better to be conservative at the beginning and start pushing a bit later. The shoes are fantastic! Steady, light, good cushion and a joy to run with.They do require good technique though, to gain the benefits.