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mark the spark
Joined: 24 Jul 2008
Posts: 11
Location: Hull
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 Posted: Thu 21 August, 2008 15:13 Post subject: WCPP testing protocols, the fitness index |
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My coaching mentor doesn't know the answer to the following question so I wonder if any other coaches here can help as I am keen to use these methods if they prove to be worthwhile.
The coaching manual specifies a Fitness Index as used by the WCPP, whereby the power to weight ratio of a rider is 'raised to the power of 0.67' in order to provide a greater indication of time trialing ability.
I understand it is supposed to represent to some degree the frontal surface area of a rider, but I don't understand what the mathematical process of 'raising to the power of' is.
If someone can enlighten me I would be hugely greatful.
Cheers.
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Ruth Eyles
Joined: 03 Dec 2007
Posts: 2
Location: Warwickshire
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| Posted: Mon 25 August, 2008 11:14 Post subject: |
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The mathematical operation of 'raising a number to a power' refers to mutiplying the number by itself that many times.
- So raising a number to the power of 2 is that number squared.
- A number to the power of 3 is that number cubed (eg. '3 to the power 3' is 3x3x3=27)
- A number to the power of 0.67 is........... well you'll need a calculator. Or since 0.67 is a round-up version of two-thirds (two thirds = 0.66666666) then something to the power of 0.67 is the cube root of its square......... you'll still probably want a calculator!
Ruth |
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mark the spark
Joined: 24 Jul 2008
Posts: 11
Location: Hull
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| Posted: Fri 29 August, 2008 15:04 Post subject: |
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Thanks Ruth,
I'll get me calculator then!
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Smudge
Joined: 04 May 2008
Posts: 2
Location: West Nofolk
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| Posted: Sat 27 September, 2008 21:26 Post subject: |
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| Wouldn't it be a matter of raising the wattage per Kilogram of body weight say from 5.85 w/kg to 6.52 w/kg. Which could either be acheived by raising Maximum 1 minute power or lowering body weight |
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Ruth Eyles
Joined: 03 Dec 2007
Posts: 2
Location: Warwickshire
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| Posted: Fri 27 March, 2009 22:47 Post subject: |
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| Smudge wrote: | | Wouldn't it be a matter of raising the wattage per Kilogram of body weight say from 5.85 w/kg to 6.52 w/kg. Which could either be acheived by raising Maximum 1 minute power or lowering body weight |
I don't think so. The WCPP Fitness Index is completely separate from the more common and straightforward power/weight ratio. It is also the ratio of power and weight, but with the weight 'raised to the power of two thirds'. This tends to reduce the impact of the weight in the ratio and reduces the advantage of the lightweight riders - I'm guessing this must be based on empirical evidence that a simple power/weight ratio favours the lightweights in a way that doesn't represent performance realities......... on flat terrain? (I'm guessing again.)
Typical Fitness Indices would be in the range 15 to 20+ but unless you know what are good/bad/indifferent values for cyclists of different abilities, gender etc the calculation doesn't get you very far. |
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mark the spark
Joined: 24 Jul 2008
Posts: 11
Location: Hull
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| Posted: Mon 30 March, 2009 08:52 Post subject: |
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Thanks Ruth,
without refering back to the coaching manual, the index is supposed to take into account the frontal area of a rider, calculated from manipulating the riders mass. Hence allowing the heavier more powerful riders further consideration, rather than just the lightweights as you say.
Clever these boffins with equations n' that eh.
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