The Science Of Why You Can't Sprint Forever



Exercise Physiology Geeks Gone Wild . . . This post is from Brian at the Wattage forum/Google Group.  No doubt some dope is being produced to spoof the bodies protective system, enabling you to product L7 power for 3 minutes at the end of a race and probably win, at the cost of frying your muscles/body at some terrifying level.





A few points that may help in visualizing glycolysis (not requiring oxygen) and oxidative metabolism (kerbs and electron transport chain).


Glycolysis has relatively fast enzyme kinetics (Km) compared with PDH
and down stream kinetics. When energy demands are higher than
oxidative metabolism can provide ATP, glycolysis is still running
“fast”, with an increase in lactate via pyruvate that is in “excess”
of what can enter the oxidative downstream component. There is some
thought that the drop in pH causes fatugue by inhibiting
phosphofructokinase 2 (control step in glycolysis), which reduces the
abilty to produce ATP, thus lowering energy production (as a feed back
to protect the muscle).
Pyruvate from glucose converted to acetyl-CoA and acetyl-CoA from fat
breakdown (beta-ox) are “competing” for citrate synthase. That is why
citrate synthase is used as a marker of increased abitliy to oxidaze
fat (and increased OBLA) because more can get past that step. 

Think of each system as its own complete loop or chain, but remember
that almost of the substrates can leave/enter the cycle at some
point. And that each control step is regulated by substrates and/or

And relating back to substrate use during exercise, fasted/fed state
and compostion of the meal/food change metabolism as well.

Andy Scott | 140 Proof | | mobile: 415-509-5915 | @andyscott999




Grab your chips, we're skiin' to Reno


Most seasons offer a window or two of cold storms that open up Eastside/Euro ski possibilities in terms of long 5k+ feet of fall line skiing on quality snow.  Tahoe is great, but the relief just isn’t there (Tahoe is at 6200′, peaks are 9ish, math is easy).   The window is decidely slammed shut right now with the recent hot storms — but just last weekend we were skiing 5k foot pow runs to Reno. Cold storms set it up, a little motivation and figuring your game out puts you in position.  No treasure map here, just treasure.


That is Tahoe, visible from the starting zone high in the Carson Range




See, it was cold. Where are we Wyoming!




The most popular shots are  gobbled up by 431 highway shoppers and Mt. Rose Ski Area refugees.  But as always, emptiness and untracked are right there given requisite experience, skills, and willingness to “see what’s over there” — oh yeah and the mind/body/gear to climb the f out if things go sideways (I am not advocating dropping in when you don’t know what is up as a general rule, and am advocating if you do drop in when you don’t know make sure you are prepared to get out from whence you came!).  Fortunately the skier population that possesses this mind/skill set is still about .00003%, talk about “all the people in the BC” be damned.  I call that “all the people at road side attractions and well-known tick list descents”.  Oh, to rant and rave!

Mellow pow turns . . .




Then a fun cliffy/rock band exploration . . .


And that was only the first 2k feet!

We started the morning in Truckee, drove to the top of Mt. Rose Highway, climbed maybe 750 feet, dropped 3k towards Reno, climbed 1.5k to lap a zone that had to be skied twice, then dropped the rest of the way to Reno, got in a car and cracked a beer at 11am and was back at my car before sunday school let out.   7000k of untracked bluebird hero pow for 2k of climbing?  I think I climbed for an hour, which was about the wait for a ride on KT over the same weekend for 25% of the vert and 13,000 times the people competing for a fresh line.

Like this.  (Friend of friend who actually makes tele turns and shuttled from Reno.  Thanks!  I predict AT within 2 years based on gear/face plant issues he experienced later in the day.  Happens.)


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