Re: Training Qs: intervals, blowing up, fat...

In article 
<2f52c1d3-bf9b-45f6-8e8b-bdd787bc4761@[EMAIL PROTECTED]
>,
 Bret <bret.wade@[EMAIL PROTECTED]
> wrote:

> On May 16, 1:29 pm, Michael Press <rub...@[EMAIL PROTECTED]
> wrote:
> > In article
> > <2b734850-7ff8-4e59-afe3-7c2aa7edb...@[EMAIL PROTECTED]
>,
> >
> >
> >
> >  Bret <bret.w...@[EMAIL PROTECTED]
> wrote:
> > > On May 15, 4:44 am, Nobody<nob...@[EMAIL PROTECTED]
> wrote:
> > > > On Wed, 14 May 2008 22:34:45 -0700 (PDT), Bret
<bret.w...@[EMAIL PROTECTED]
>
> > > > wrote:
> >
> > > > >On May 13, 4:50 pm, "Off The Back" <marco_fenne...@[EMAIL PROTECTED]
>
wrote:
> > > > >I don't know that you can train a sprint much. What's your
experience
> > > > >with that?
> >
> > > > >It's also interesting that we tend to analyze racing with models
from
> > > > >our profession. For me it's:
> >
> > > > >Aerobic power = Battery
> > > > >Endurance = Battery life
> > > > >Anaerobic power = Capacitor
> > > > >Recovery = RC time constant
> >
> > > > >It works for me, but not for anyone else I've met. Many don't
even
> > > > >recognize that there are that many variables.
> >
> > > > >Bret
> >
> > > > Interesting: From Wiki:
> > > > "In an RC circuit, the value of the time constant (in seconds) is
> > > > equal to the product of the circuit resistance (in ohms) and the
> > > > circuit capacitance (in farads), i.e. ? = R × C. It is the time
> > > > required to charge the capacitor, through the resistor, to 63.2 (?
63)
> > > > percent of full charge"
> >
> > > > So what is 'resistance' to you? Motivation?
> > > > Circuit Capacitance=Anaerobic power?
> >
> > > > Cool analogy.
> >
> > > Maybe a sloppy analogy. The RC charging  cycle is non-linear because
> > > the charging current drops as the capacitor charges due to the
> > > transition in voltage drops. This is like trying to pump up a tire
to
> > > 100 psi with a compressor whose tank is at 100 psi. Initial air flow
> > > will be high but will fall to zero as you approach 100 psi.
> >
> > > I'm not sure that muscle recover has a similar mechanism. Here's
what
> > > I found about muscle recovery from anaerobic exercise which seems to
> > > involve two separate phases:
> >
> > > "It is suggested that the initial fast phase of CP resynthesis is
> > > limited by the availability of oxygen whereas the subsequent slow
> > > phase is limited by the hydrogen ion trans****t out from the muscle."
> >
> > > The oxygen dependent phase is presumably linear since oxygen is
> > > constantly supplied. I don't know about the hydrogen ion dependent
> > > phase. I'll stop pretending I know anything about biology here.
> >
> > > Resynthesis of creatine phosphate in human muscle after exercise :
> > >http://www.ncbi.nlm.nih.gov/pubmed/43580
> >
> > In the cell energy delivered for use comes from ATP
> > hydrolysis. This produces H+. H+ diffuse into the
> > mitochondria and is metabolized. When the mitochondria
> > are working at capacity excess H+ must be buffered then
> > physically removed from the cell.
> >
> > A good survey article is
> >
> > Biochemistry of exercise-induced metabolic acidosis.
> > Robert A. Robergs, Farzenah Ghiasvand, and Daryl Parker
> >
> > <http://ajpregu.physiology.org/cgi/content/short/287/3/R502>
> 
> If I read this correctly the CP resynthesis should speed up over time
> during recovery as the H+ created during exercise is cleared? If so,
> then there is no negative feedback to CP resynthesis and my analogy is
> bad.

I do not know. The authors do not say much about
creatine phosphate. 

"The cellular store of creatine phosphate 
provides a near immediate metabolic system to produce ATP 
during the onset and initial seconds of muscle contraction. 
Creatine phosphate is also believed to be im****tant for the 
general transfer of phosphate groups from the mitochondria 
throughout the cytosol, and as such could also be im****tant for 
all metabolic states of skeletal muscle cells. "

"On the basis of the biochemistry presented thus far, Fig. 14 
indicates the ****ft in proton þux as exercise progresses from 
steady state to nonsteady state. Central to the cellular proton 
balance is the hydrolysis of ATP required to fuel cell work, 
such as muscle contraction. This is clearly the main source of 
proton release in contracting skeletal muscle, and when the 
NADH and protons from cytosolic reactions are produced at 
rates in excess of mitochondrial capacity, cytosolic redox is 
aided by lactate production, which essentially accounts for the 
proton release from glycolysis. However, as the rate of ATP 
hydrolysis exceeds all other reactions, the rate of proton release 
eventually exceeds metabolic proton buffering by lactate pro- 
duction and creatine phosphate breakdown, as well as proton 
buffering by Pi, amino acids, and proteins. In addition, once the 
maximal capacity of lactate/proton removal from the cell is 
exceeded, proton ac***ulation (decreasing cellular pH) re- 
sults. Also, note that Fig. 14B clearly shows that the origin of 
the ac***ulating intramuscular Pi is ATP hydrolysis, not 
creatine phosphate breakdown, which is still mistakenly inter- 
preted by many physiologists (59)."

The abstract of the Sahlin K, Harris RC, Hultman E
article suggests that mitochondria respiration is
responsible for CP re-synthesis. 

I gather that excess H+ from anaerobic effort is only cleared
by trans****t out of the cell.

-- 
Michael Press