Adamant to improve my personal best on this notoriously tough course, my goal time was 2:50. Things were looking good at the half way mark (1:22:30). With my heart rate below my threshold value (and also below what it was my previous marathon), I was feeling good and had “time in the bank”. Unfortunately, the wheels fell off shortly afterwards at the 28 kilometer mark! With a second half split of 1:36:01 (i.e., a +14 minute split), one could imagine how painful the long slog back to the finish line was!
In hindsight, I was too ambitious on my goals for this race. I have done the Rotorua marathon twice before, and just like this time, I also had a horrible second half (read: greater than 10 minute split)! Ironically, the “wheels” also fell off in a similar fashion to my 2015 Rotorua Marathon):
Although heart rate is a indicator of workload, I suspect a contributing factor to my second half demise was going down the hills too fast. Carelessly racing down hills causes a lot of stress on your knees. Meanwhile going up hills too fast can also strain the body as its easy to go into lactate threshold territory. In this case, lactic acid begins to accumulate faster than the body can convert it back into energy. I’ve felt this on runs before and made sure to take it easy up the hills. Nutrition could have also played a key role, but I had a similar diet before and during the race compared to some of my previous marathons.
Race weight was around 77kg and I took an energy gel at 9.3km and 27.8km. I had a third spare gel which I didn’t use. I also took a drink at each aid station (either water or Powerade).
Back to the drawing board.