A.M. Did my strength test again. See how long I can hold 5:20 without having to sprint. So I did 79, 80, 80, 82 (5:21). Not good. Jogged some, decided to try again to see if the failure comes sooner. 80, 80,80, 80 (5:20), 83, 82 (8:05 for 1.5). Hmm... That is the oddest pattern. How does that work? You would expect that after getting to the point of not being able to run another 80s quarter without a significant effort I would not be able to return to the same condition after only 10 minutes of jogging. A possible explanation is that my slow twitch fibers cannot go faster than 5:30. So if I want to run 5:20 I have to recruit fast twitch, and they fatigue after about a mile. Fast twitch recover pretty fast, and are ready to go again after 10 minutes of jogging. Slow twitch are not fatigued, in the meantime, they just cannot go fast enough.
The feeling is also rather odd. At 80 the stride feels relaxed, like I am only recruiting a fraction of power. Then when I slow down, all of a sudden it feels like I am recruiting every fiber there is to recruit, like I am trying to squat with maximum weight. That does go along with the fast twitch fatigue explanation. It takes only a fraction of fast twitch power to run 5:20 pace. But it does take all of the slow twitch power to run 5:30 if the fast twitch are not helping.
Ran with the kids Benjamin did 4, Jenny did 3, Julia and Joseph did 1.5.