How do I maintain increased speed beyond the grinding wall
(Chico, CA, USA)
Q: I have run a 72 mile 24 hr run, 2-50 mi, 1- 100k.
I have been playing with running at 70% of my heart rate. I ran 19.5 miles yesterday and my Garmin shown 2775 Calories used. I took in aprox. 700 Cal. in liquid Carbs. At the end I was maintaining speed but was starting to feel the signs of needing to slow down. It appears that I will hit the grinding wall when I run out of stored fuel and the available fuel is only what I take in. Reduced energy=reduced speed. Premise: the body can only process 220 Cal. intake an hour while running. Answer from Anna
Thanks a lot for your detailed report and question. The answer is actually fairly easy and not scientific. It's true that the body is capable to absorb between 180-250 cal. per hour and that there is usually a deficit from what you've burnt in comparison to your intake.
Key is to start fueling in the first hour to prevent early glycogen store depletion. Aim to ingest liquid or solid fuel after 45 mins. and continue with the rhythm. It's best to consume calories every 20-30 mins. rather than once per hour to maintain more balanced blood sugar levels.
What is even more important than regularly fueling the body is to put high importance on adequate running training that is geared to build stamina in the legs.
The best session to reach higher levels of performance is the back-to-back run consisting of 2-3 long runs on two or more consecutive days run at a pace slightly above your comfort pace. The second long run of such a block will feel quite hard to do at first since your body is fatigued from the efforts on the previous day.
Over time, literally within weeks, you'll notice how much stronger your legs and overall stamina are so that when you hit the famous 'wall' in training or in a race again, you'll be able to push for longer without necessarily slowing down.
Back-to-back runs are an integral part in ultramarathon training and should be done every week.