onsdag 28. juli 2010

What it Takes (To Qualify).

Alan Couzens har skrevet en meget interessant artikkel om hva som kreves av "fitness" for å kvalifisere seg til Hawaii. Betraktningene gjelder for en mann, og er veldig relevant når man skal vurdere seg selv, eller planlegge tilstrekkelig trening og testing.
Spesielt evnen til å forbrenne fett er avgjørende - og den trenes blant annet på langturer (som en del mener er unødvendige). Med tilstrekkelig energifrigjøring fra fett (på nødvendig intensitet - konkurranseintensitet), og med tilstrekkelig Critical Power 5 minutes (CP5) - over 400 Watt - så er man i utgangsposisjon. Og så er det alle detaljene, ernæring, Aero posisjon, løypevalg, tid i T1 og T2, fokus og mental styrke osv.

Han skriver følgende:

"The major difference between the novice and the Konee when it comes to long duration fueling comes from the energy contribution from fat.
Based on our lab testing, athletes who qualify for Hawaii are typically generating >33% of their energy needs from fat (~300kcal/hr). This is an important adaptation and one that can be limiting for a lot of athletes with V8 power but lousy fuel economy.
By generating 5kcal/min from fat, a 10hr Ironman gets an additional 2800 calories of work done over the course of a 9.5hr Ironman. Add in ~2400 cals of worth of energy from exogenous carbs (gels, sports drink etc) and we’re up to ~8500 cals worth of energy to play with.

So how much fitness do we need to get 8500 cals of work done over 9.5hrs? 8500 cals of energy output over 9.5hrs is equivalent to ~230W of power on the bike. Now, as outlined above, we want this 230W to occur within the zone of max fat oxidation (~60-65% VO2max) This infers that the athlete has a VO2max of ~5L/min at an economy of 75W/L. These numbers also pre-suppose that a 230W output will ‘get the job done’ and get the athlete from A-B in ~9.5hrs. Based on my calcs, probably true for a 75kg athlete with decent position over a well paced flat course. Much bigger or any less aero, and the athlete will need more power.

So, in relative terms we’re talking about a VO2max in the neighborhood of 65ml/kg, equivalent to 5K speed of ~17:30 and a CP5 of ~400W. It goes without saying, that this represents a very high level of aerobic fitness: 1 in 200 fitness for a young male, 1 in 10,000 fitness for a 40-49 yo guy based on the Cooper Institute’s data! It is also worthwhile remembering that this level of fitness is not sufficient if not paired with appropriate race specific endurance. If it is paired with a high level of fat oxidation and an AeT of >60% of VO2max, the athlete will be in a good spot for their Kona assault."

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