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Understanding power (or not...)

I’m new to triathlon so please excuse this if the following is a ridiculous point to make:

I’ve been reading a fair bit about power meters and I really like the idea of being able to measure effort accurately whatever the conditions. From what I understand, general wisdom suggests that the best way to use power readings would be to attempt to maintain uniform power for the duration of the race. I wonder whether this is incorrect?

For example, wouldn’t increasing power output down hill as compared to on the flat deliver more bang per watt? Surely marginal speed increase per watt will be higher down hill, so wouldn’t it be optimal to use more effort down hill than on the flat???

I also understand that by increasing power output down hill I will have to pay back more than enough in other sections to make up for the extra exertion. Is there, however, a disproportionate reduction in average speed associated with using less power on up hill sections???

I would really like to see this graphed out because I reckon the following could be the way forward:

• More effort down hill increases average speed by the greatest amount, therefore ride at above average effort on down hill sections (+ 5 or 10% depending on length of section)
• Less effort up hill decreases average speed by the greatest amount, therefore ride at average effort
• Always use flat sections to recover at effort levels below average (- 5 or 10% depending upon length of flat) until HR returns to target HR.

As I do not own a power meter I have no way of trying this out, however, if it was to be tested over a known distance, I’d be interested to find out the effects on:

a) time
b) average HR
c) perceived exertion

If the above is absolute nonsense, I appologise for wasting your time, ha ha!

Cheers for now!

Davy

Comments

  • ollybollyb Posts: 11
    Hi Davy

    I think you might be over analysing it a bit,to be honest. Power is just a measure of how much work you're doing, and is completely intrinsic to you, not affected by external factors, so is a fantastic way of tracking progress and devising sessions.

    Training by speed,for example, doesn't work as variations in gradient on different routes, and variations in wind resistance mean you can't compare one day's work to another's. Heart rate is better, but but still can be affected by hydration, stress, etc. Power overcomes these issues and gives you a true figure for the work you've done.

    Back to your example, you wouldn't necessarily use power to determine what effort to do on hills and flats, it would be a more useful measure of how well you did on that course from week to week. It also allows you to devise sessions such as the Hour of Power.

    Buying a powertap was the best thing I ever did for my training!
  • Cheers for that olly, I probably am getting ahead of myself a bit!!

    Anyway, considering that I am skint and WAT is currently through the roof, do you know where I might find a reasonably priced power meter? I've had a good look on wiggle etc and they seem to be coming in at £800+!

    Davy
  • ollybollyb Posts: 11
    You can rent them from cyclepowermeters.com to see if they're for you. For best effect most people use an application called WKO+ (http://www.trainingpeaks.com) and a full understanding of terms such as FTP,IF, TSS, CTL, ATL, TSB are essential Take a look at [url]alex-cycle.blogspot.com[/url], Alex has lots of really useful info on there.

    Finally, the book "Training and Racing with a Power Meter" (see Amazon) is meant to be really good.
  • ZacniciZacnici Posts: 1,385
    Hi - agree with Ollyb - useful but do not be a slave to the machines - the one machine that counts is yourself. It does not matter the slightest if an HRM or powermeter says you can push out a bit more if you are feeling rough, dehydrated etc then that is what really counts.

    Re putting in effort downhill and cruising/below effort on the flat, not many courses have lots of downhills and minimal flats and uphills. Look at it this way, you will probably have the same distance going up as going down and consequently spend more time going up. If it takes 2 minutes to go down and by monumental effort decrease that by 25% you save 30secs. If it takes you 5 minutes to go up that hill and can decrease that by 10% you save 30secs.

    This harps back to previous discussions re gearing; one school of opinion says go high gear so you don't spin out coming downhill and the other gear for easier hill climbing and if you spin out put your feet into the most aerodynamic configuration, put your chin on the front tyre and enjoy the recovery.
  • ollybollyb Posts: 11
    Hi - agree with Ollyb - useful but do not be a slave to the machines - the one machine that counts is yourself. It does not matter the slightest if an HRM or powermeter says you can push out a bit more if you are feeling rough, dehydrated etc then that is what really counts.
    Exactly. A real problem that a lot of people fall into is over analysing the power they're pushing out every ride (including myself). Why why why was my normalised power 2 watts lower than last week???? Arrrrrrghhh!
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