Wheras yesterday I did a fast 5 km (in 20:10), I ran most of it in zone 4 and 5. This was quite a hard pace. Today I focussed on a trainingsblock that included a marathon pace effort - during that block I was staying in zone 3 and 4. My pace today was not that much slower compared to yesterday, but those few seconds make a world of difference. This has to do with your lactate threshold - if you run faster than your lactate threshold you will accumulate lactate faster than you can use / remove it and quickly be forced to slow down. For me, my lactate threshold is +/- 4:07 min / km - if I run faster, I can maintain that for quite some time but it gets hard real fast. As a marathon runner - you won’t be able to run the entire marathon above your LT. The key is to stay slightly below that LT during a marathon - that way (if all other conditions are working with you , like the weather) you should be able to maintain your pace for the entire run. Still hard but much more managable.
Doing LT runs during your training helps you to increase your Lactate Threshold (and thus helps you maintain a stronger pace during the race)
Normally you won’t be doing two hard sessions in a row, but I will be going on a mini trip tomorrow so I decided to squize in a quality session today! This turned out to be a good call, there was some rain, temperature around 0 C and I didn’t bring any light with me (running in the dark) - some speed work felt perfect!
I did 1.5 km warmup (zone 2 - low zone 3), then moved up to 1.5km at my current marathon pace (4:16 / km) before doing 4 km around my goal pace 4:05 - 4:10 / km. I closed the training with 3 km slow cooling down.
I felt strong and had lots of fun!
Happy running