wellnow wrote:
Seb Coe did a pretty good job of running at good endurance paces with all his FT fibers. Fast intermediate fibers are much more efficient at burning glycogen than you give them credit for.
Actually ... they're not. But every FT I ever met tried to convince him/herself of that right up until they met a real-life ST.
You offer Seb Coe as a prime example. Do you really have to go back to the late-70s, early/mid-80s to find one? Can't find one more recent who did well?
Besides, wasn't Coe's best work done at 800-1500-mile? Hardly "good endurance" distances, don't you think?
Since you mention him, let's quote from the book his Dad co-authored with David Martin. (p127, 1991 edition)
% Energy Contribution
Event — Phosphate — Lactate — Aerobic
800 — 5 — 38 — 57
1500 — 2 — 22 — 76
3000 — 1 — 12 — 88
5000 — ``1 — 7 — 93
So, his best performances actually came at distances where the aerobic contribution was low (compared to 3-5k)
PR's (source, wikipedia)
800 m — 1:41.73 — 1981
1500 m — 3:29.77 — 1986
Mile — 3:47.33 — 1981
3000 m — 7:54.32 — 1979
5000 m — 14:06.2 — 1980
Those ("poorer quality" and I'm talking relatively) 3000/5000m PRs would seem to contradict your statement that Coe "did a pretty good job of running at good endurance paces with all his FT fibers". The longer the distance, the "worse" (in terms of quality) his performances became. Granted, he may not have focused on those longer distances as much as he did on the 800-1500, but it seems safe to assume that if he had felt that his talent lay in the longer distances, he would have done so. Coe just found his perfect niche and stayed within it, and there's nothing wrong with that! (In this way he was much like Wilson Kipketer who would not alter his training to even allow for 800-1500).
And before you do, don't tell me what Coe would/coulda/shoulda done at 5000. Let's just stick to the facts.
So, here's the deal. As an FT moves up in race distance he/she becomes ever more vulnerable to those who are more-gifted as ST's (definitions are mine).
Here's a neat study that shows exactly what I have been getting at in the diff between ST vs FT:
14 competitive cyclists with similar oxygen uptakes (range: 4.6-5.0 l/min) were compared for blood lactate response, glycogen usage, and endurance during submax exercise.
Seven of the group reached LT during exercise at a relatively high intensity.
Group High — LT = 81.5% VO2max. Years spent cycling: ~5.1
Seven of the group reached LT during exercise at a relatively low intensity
Group Low — LT = 65.8% VO2max. Years spent cycling: ~2.7
When cycling at 88% VO2max
——————— VO2max ———— %VO2max ———— Time to Fatigue ———— BLa immed.
——————— ml/kg/min———————————————— (mins) ————— post-exercise mM.
Group High ——— 68.6 ——————— 88.5———————— 60.8 ———————— 7.4
Group Low ——— 66.0 ——————— 88.0———————— 29.1 ———————— 14.7
Notes:
1) The average time to fatigue was more than twofold longer in Group H than Group L.
2) At fatigue, the BLa was approx half as high in Group H as in Group L.
3) Inference: Group H must have used less muscle glycogen than Group L (see next table)
Muscle glycogen utilisation and CHO utilisation during 30 mins exercise in groups High and Low (means)
——————— %VO2max ———— %HRmax ———— BLa mM ———— Total CHO ———— Glycogen used
——————————————————————————————————— (mmol) —————— (mmol/kg)
Group High———— 79.4 —————— 84.6 —————— 2.8 ———————— 358 ——————— 27.9
Group Low———— 79.3 —————— 89.8 —————— 6.2 ———————— 605 ——————— 65.4
Notes:
1) The exercise intensity and duration were chosen to stimulate substantial carbohydrate oxidation in all subjects.
2) The calculated amount of CHO oxidation was 69% greater in Group L than in Group H.
3) Glycogen utilisation was inversely related to % VO2max at LT. (The LOWER the %Vo2max at LT, the MORE the cyclists burned glycogen)
Muscle characteristics of Group H and Group L
——————— % Type I (ST) ———— %Type II (FT) ———— Mean Fibre ———— Capillaries
—————————————————————————————— Area ——————— (mm2)
Group H ———— 66.7————————— 33.3 ————————6,930 ——————— 405
Group L ———— 46.9 ————————— 53.1 ————–——— 8.132 ——————— 327
Notes:
1) The combination of %VO2max at LT and capillary density (per square mm) accounted for %%93% of the variance in performance and proved to be a quite accurate predictor pf time to fatigue at 88% VO2max.
Notes from a Discussion (by the authors)
1) Endurance during submax exercise is closely related to the factors that control muscle glycogenolysis and BLa concentration.
2) The data indicate that glycogen utilisation during exercise at 79% VO2max can vary more than twofold when comparing subjects matched for VO2max, but who reach LT at widely differing percentages of VO2max.
3) The training variables and aspects of muscle morphology that accounted for a large portion of the observed variance in %VO2max at LT and glycogen usage while cycling were:
a) years engaged in cycling training
b) percent Type I muscle fibres.
(in contrast to what wellnow often states that mitochondria and capillary density are quickly maxed with training) the authors state:
"It appears that intense cycle training performed for ~5 years compared to 2-3 years promotes continued neurological and/or muscular adaptations that reduce glycogenolysis specifically when cycling."
Further Notes
Noakes remarked in one study that (black) South African runners had lower BLa values at all paces when compared to matched (white) South Africans.
Saltin conducted a major study of Danish boys and Kenyan boys (from town and country) and between elites in both countries. In the diff between Elite Kenyans and elite Danish runners, allow me quote two statements:
"Kenyan elite runners had lower plasma lactic acid concentrations than Danish elite runners at submax running speeds, also when related to oxygen uptake."
"The activity of the HAD enzyme was markedly higher in the muscles of the elite Kenyan runners, indicating that they have a better ability to utilise fat while running compared to Danish runners."
Final comment:
The whole point of Hadd's Phase I is to maximise the running pace at which significant fat-burning can take place and thus move the LT to higher and higher velocities before having to turn greater percentages of glycolysis for energy. Two points: a) as running pace increases burn as much fat for as long as possible and b) postpone a rise in BLa as long as possible.
Don't burn muscle glycogen until you absolutely have to (and when you do, Phase II will train you to clear it as quickly as possible and improve your LTP).
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As in the other recent threads, I do not intend to contribute any further here due to commitments elsewhere. Thanks for all the interest shown in the topic.
Hope these tables/columns come out okay.