Why train with power?

Leroy42

I haven't had my PM for very long so perhaps I am missing something but with the constant changing nature of power output I find it difficult to use it during the interval itself, its more something to review afterwards.

HR however is fairly consistent. When I start a climb for example, my HR will climb fairly quickly (under a minute) to near enough my LTHR and then I can hold it there relatively constantly. I know (or at think I know) my LT so even if my PM is reading low watts I know that by pushing beyond my LTHR I will burn up very quickly.

At the moment I can only see the turbo as the place to use power on an actual basis as the ride is consistent, there are too many variables acting on us outside to make it as useful as HR.

To go back to the previous examples of high heat etc, surely if your HR is at LT and your power is down then you can't simply raise your power up, is that not against the concept of LT?

ric/rstsport

Leroy42 wrote:

I haven't had my PM for very long so perhaps I am missing something but with the constant changing nature of power output I find it difficult to use it during the interval itself, its more something to review afterwards.

the power meter should be a guide. it shouldn't be prescriptive

HR however is fairly consistent. When I start a climb for example, my HR will climb fairly quickly (under a minute) to near enough my LTHR and then I can hold it there relatively constantly. I know (or at think I know) my LT so even if my PM is reading low watts I know that by pushing beyond my LTHR I will burn up very quickly.

everyone's HR varies significantly at the same exercise intensity (power output) due to a variety of issues, including, but not limited to (and in no particular order):
1) temperature
2) cadence
3) altitude
4) stress/anxiety
5) fatigue
6) caffeine
etc

for clarity, "LTHR" is the wrong term to use.
1) lactate threshold has absolutely nothing, whatsoever to do with HR. Lactate threshold (LT) is the *work rate* (power in cycling, m/s or km/hr in running) associated with a specific rise in lactate, which requires blood to be taken to measure the said lactate
2) because HR varies significantly at a specific power output (as mentioned above) you can't say that there's a HR associated with LT
3) LT is usually defined within the literature as the work rate that either elicits a fixed lactate measure of 2.5 mmol/L or the rate that elicits a 1mmol/L increase over exercise baseline levels, which would be 2point something for everyone!
4) either of the definitions in 3 would produce a power output that is about 10 to 15% below your best ~one hour TT power and could be maintained for about ~3 hours

If your PM is reading low, or high. Then it's useless. As a minimum it should be zeroed prior to every ride to make sure the offset is correct, and it should be calibrated against known masses

You can ride (anyone can) significantly above your "TT HR" in certain conditions (e.g. a very hot environment)

At the moment I can only see the turbo as the place to use power on an actual basis as the ride is consistent, there are too many variables acting on us outside to make it as useful as HR.

To go back to the previous examples of high heat etc, surely if your HR is at LT and your power is down then you can't simply raise your power up, is that not against the concept of LT?

while a turbo is a great place to use power and get a consistent effort in, it's different to the road or track. Power varies in what appears (but isn't) to be a stochastic manner. So, tiny changes in road grade or wind speed seem to make it vary. this is normal. also if press harder coming out of corners, or marginally ease up. In other words, as you'd expect, a power meter is sensitive.

additionally, it's worth noting that if you have a Power Tap you have a set of issues that appear to make power incorrect due to the way that power is calculated with a rotating wheel, rather than pedal cadence. this makes power appear jumpy.

i find it best to display power averaged over several seconds, but to record power at 1-sec intervals. And not to chase numbers.

Ric

Intherain

Interesting thread. I would love to train with power but it's just too expensive for me at the moment, although the Stages offering looks attractive.

At the moment I have to use HR and RPE as its the only thing I have to work with. Am I correct in thinking that if I ever bought a power meter its best to train using power in conjunction with HR or should HR just be disregarded and you focus on the power output?

amaferanga

Intherain wrote:

Interesting thread. I would love to train with power but it's just too expensive for me at the moment, although the Stages offering looks attractive.

If you can afford a Stages then you can afford a proper power meter such as PowerTap or Power2max. Seriously, don't buy a power meter that only might be giving good data.

cougie

DC Rainmaker seemed to rate the Stages meter pretty highly against the opposition. Powertap looks good - but I'd rather have it in the crank than on one wheel.

cougie

So long as its consistent - it shouldnt be too much of a problem.

amaferanga

cougie wrote:

So long as its consistent - it shouldnt be too much of a problem.

That's only going to happen if your L/R balance never changes and that's the problem. L/R balance depends on many things such as cadence, fatigue, power output, position on the bike, etc. Might get a bit tedious only comparing intervals where conditions are identical. Now if Stages was a couple of hundred quid then it'd be worth considering, but when you can get a proper power meter for the same money or even a bit less then Stages makes no sense at all.

cougie

What I like about stages is that I could train on the winter bike with power and then swap the crank to the race bike when I need to. Powertap isnt as easily transferable. What would you advise amaferanga ? Any bargains out there ?

wallace_and_gromit

Ric/RSTSport wrote:

everyone's HR varies significantly at the same exercise intensity (power output) due to a variety of issues, including, but not limited to (and in no particular order):
1) temperature
2) cadence
3) altitude
4) stress/anxiety
5) fatigue
6) caffeine
etc

No surprises with this list. A few observations of my own, based on years of rowing on a Concept2 powermeter/rowing machine and turboing with a speedo...

1 - Although you can get a higher heart rate more easily when it's hot, in general, what you generally get (8 time out of 10, give or take) is a slower speed with normal heart rates when it's hot.

2 - Interesting one this. On a rowing machine, you could vary the rating (i.e. strokes per minute) within quite a range (e.g. 24+/-2) to shift the focus of the pain from legs to lungs, but ultimately this had very little impact on ultimate performance and heart rate. I've never experimented with cadence on a bike, as I pedal in the lowest gear I can to ease the burden on my dodgy back.

4 - In my experience, this only affects low heart rates. Once you're working reasonably hard, normal relationships apply. In fact, an hour "at threshold" on the turbo or rowing machine is a great disperser of stress.

5 - Agreed. I always do a standard warmup and if my heart rate is significantly above normal, I put this down to fatigue and have a rest day!

6 - Similar to stress/anxiety, and often the two go together.

cougie

Well no - but the wheel I'd use for winter wouldn't be the wheel I'd race on.

Ta for the tips though - I shall follow this up !

buckles

cougie wrote:

What I like about stages is that I could train on the winter bike with power and then swap the crank to the race bike when I need to.

This is EXACTLY what I do with my Power2max, and the great thing is that the power measurement comes from from both my legs

Seriously, I would buy Stages power meters if they were half the price of a Power2max but they're not competetive on price and not that much easier to swap.... yet it's only half a product... what's the attraction?

cougie

Luke - what about this powermeter ?

Used Ex-Rental powertap SL Wired Wheel System

32 Spoke Wheel built onto Mavic Open Pro rim

Complete wired system comprising
Wiring Kit
Head Unit
USB Downloader
Poweragent Software

6 Month Warranty - See more at: http://www.cyclepowermeters.com/used-ex ... Rb2SS.dpuf

Is wired much more of a hassle than wireless ? I'd imagine I'd want to swap the kit from training bike to race bike come the warmer months - and would the wired system send data to a laptop for trainerroad etc ?

cougie

Cheers for that - I'll go check what my piggy bank has in - see if I can afford wireless.