ridecamp@endurance.net: DOMS

DOMS

Tivers@aol.com
Tue, 22 Apr 1997 23:10:38 -0400 (EDT)

TI:
> Immediate post-ex glucose feedings are not intended for glycogen
resynthesis
> but for recovery and avoidance of Delayed Onset Muscle Soreness. I don't
know
> what part feeding post ex plays in glycogen resynthesis because at that
point
> the liver is very active in that regard.

Beth:
>>Actually, immediate post exercise carbohydrate feedings are exactly
intended to promote glycogen synthesis.
One of the most important limitations in endurance performance is the
depletion of glycogen in the working muscle. The resynthesis of
muscle glycogen during the recovery period is therfore an important
metabolic process that is dependent on adequate carbohydrate intake
[Costill et al 1992, Holloszy and Booth, 1976]. In humans,
carbohydrate rich sources immediately following exercise and at 2
hour intervals follwing cessation of exercise have been shown to
augment the replacement of muscle glycogen [Ivy et al 1988]. Delaying
the feeding by several hours in these studies reduced the glycogen
rate of storage by about 50% [Reed et al 1989]. >>

That's one perspective, but muscle glycogen replenishment is slow, so
doubling its rate is not big deal--from about 2% to 4% per hour in a 1996
paper by AJ Vandenbergh, et al, when comparing fat feeding post ex vs
glucose feeding: "The muscular glycogen concentration was expressed as a
percentage of the glycogen concentration measured before exercise. The
glycogen recovery rate during GF (4.2 +/- 0.2%/h) was significantly higher (P
< 0.05) compared with values during FF (2.2 +/- 0.3%/h)."

So we're not talking about some miraculous pumping up of muscle cells with
fuel after carbohydrate feedings closely post -ex. Yes, providing substrate
in the diet obviously will aid muscles in glycogen resynthesis, but it's not
a huge effect. You're still stuck with 20+ hours of recovery.

The DOMS story is more dramatic in effect, especially for those who routinely
encounter horses than cannot be exercised for several days due to post-race
muscle soreness or stiffness. I'm not going to go out and dig up the papers
I've read on DOMS and immediate post ex carb feedings, but there have been
more than one (1996-7) demonstrating reduced DOMS with quickened (within 1
hour) post-ex carb intake. This is also what we're experiencing in our
racehorses--significantly reduced stiffness. I believe we also have some
endurance horses which have exhibited same.

>>What is the supposed basis for glycogen in diminishing delayed muscle
soreness? Muscle soreness has been correlated with collagen breakdown
but not blood lactic acid levels [Schachat,1980]. >>

There's no need to retreat to the 16th century to find papers to clutter our
discussion--why not agree on materials less than 10 years old? Yes, we know
lactic acid has nothing to do with muscle soreness and stiffness. Instead, it
is the initial over-exertion/traumatic damage, followed by
free-radical/inflammatory attack that causes post ex muscle soreness and
stiffness. By providing energy early to the damaged muscle cell, recovery
activities, including sweeping away of debris and damaging chemicals, you
reduce the continuing damage of the tissue, just as you would an injured
tendon.

>> The preponderance
of evidence at this time points to the "torn tissue" theory of muscle
damage as a cause of delayed soreness. In that light, I am unclear
as to the role of post exericise carbohydrate intake in avoiding
soreness. Interested to hear of any literature that might state
otherwise.>>

We're talking about severity and duration, not initial cause. Perhaps a scan
of the science involving post-traumatic free radical damage, additional
necrosis caused by circulatory compromise, etc. would clarify your
understanding of the benefit of having fast energy available, not
exclusively for muscle cells, but for the heart, vasculature and other
organs, to hasten the cleanup?

Actually, I think I read the DOMS stuff in Luke Bucci's Nutrition Applied to
Injury Rehabilitation and Sports Medicine.

ti

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