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Experience Report: 2019 Joshua Tree Double Century
Related: double century, electrolytes, exercise, hard core, Joshua Tree Double Century, ultra endurance exercise
Joshua Tree Double Century was run out of the usual motel in Twenty Nine Palms, CA. This year the course was permitted to run through Joshua Tree National Park, including the climb to Keys Road lookout.z
Going out, it was very cold at 5:40 to 7 AM, reading 34°F / 1°C for 20 miles or so, rising to a balmy 39° at the top of the Keys Road lookout.
As usual I soloed (no drafting), leaving alone at 5:40 AM. By the top of Keys View, I had caught 56 riders, most of whom had left 70 minutes ealier or more. By Chiriaco (mile ~90), I had ovetaken all but 3 riders (according to the rest stop folks at Desert Center). And there things stayed until the end, but at mile ~95 I lose 25% of my power, suddenly.
Fear of fast
With the Southern Inyo Double Century done the Saturday prior, I had a lot more confidence in my fitness (excellent, 2-day recovery) but I remained concerned as to whether I could do any fast descents (the post-crash fear/anxiety at speed that I had to Southern Inyo Double.
As it turned out, I was fine descending from Keys View Road at ~35 mph, though that is only a ~3% grade and no cliffs to install fear, and with excellent smooth bump-free pavement. I had mentally worked on the speed-fear for the week prior and made progress, but I still cannot manage high-speed steep descents without visualizing myself in a mangled heap. Hopefully that will fade.
Strategy, issues, etc
I was concerned about having to pee too frequently as at SIDC, so I did not drink much for the first 2 hours or so, but had nearly 2L of fluid by mile 66, where I resupplied with four 1-liter ottles each with 250 calories of Tailwind @AMAZON. I had also consumed some GU energy gel by then, perhaps 300 calories worth.
Still, by mile 90 (five hours or so in) and with a 3200 calorie “burn”, I had taken in only ~700 calories. That should have been enough by the numbers (22% of expenditure is spot-on), but in the space of 2-3 minutes at mile ~95, I went from rocketing past Chiriaco Summit at ~230 watts to a major loss of energy/power to piddle along at ~180 watts. Something just shut off in a very short time period. When this sort of thing happens (many times in many doubles), it takes hours to recover regardless of nutrition. Not until mile 180 or so did I finally get back to ~200 watts and feel sort or right again, but I had been dealing with knee (patella) pain for 50 miles, and could no longer utilize my strength.
Here’s the thing: my muscles were not at all tired when done, as proven by a 2300 calorie hard workout with the highest power (watts) of the year only 36 hours later. Clearly there was no muscle fatigue issue involved at all during the double (I had no sense of fatigue nor soreness), and muscles don’t just get tired over a few minutes after working great for 5 hours. And recovery was almost literally overnight. Just not a fitness issue at all, and that hard workout was with the lowest HR of the year and a sense of ease, indicating excellent recovery.
So what the hell happened during JT?
As I was totally loaded with glycogen prior (I have a dietary routine to do so over 2 days), I did not expect so early an energy dip/loss. But averaging 225 watts for about 5 hours apparently took its toll, perhaps draining my body of glycogen? Still, I did not feel tired at all, in fact I felt robustly strong up through Chiriaco summit.
How could I average ~225 watts for five hours(a blistering pace for double) then have it all go to hell in the space of a few minutes? Maybe it is/was a fueling issue. And maybe not.
I cannot rule out central fatigue (intracortical excitability causing decreased neural drive from the motor cortex to the muscles), e.g., a brain fatigue.
I really need to sort out the cause—if I can, I should expect to finish an hour faster on such a ride, which would put me into the top 2 or 3.
See Sodium and Electrolute Losses During Prolonged Exertion.
