I do not have a power meter on my bike but they have one at my gym. I was wondering if the numbers they give are anythink like what you guys are getting on your bikes.

I've been using a Polar 725 HRM with the optional power kit.

Only been using since Feb '05. My max power output peaked at 1,037 watts. Steady riding on the flat, I haven't looked into in detail. I think from memory between 200 watts and 300 watts.

I do have doubts over the Heart Rate (HR) monitors you get in gyms (the type that get their readings from shiny metalic handlebars on spinning machines. My HR showed as 190 for much of the 20 minute ride I did. Yes I was flat out, 100% effort, but with a true HR of 190, I'm pretty sure I'd be dead.

I'd say it was over reading by around 8%, as I calculate my Lactate Threshold (sustainable pace for 20 minutes) as being 175 (max of 198).

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"Ride it like you've just stolen it!"

Are you sure? I thought (read) that Lactate Threshold is between 12 to 18 bits below your maximum.

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Now up on the hill is where you find us…..

Lactate / Anaerobic Threshold is not a set number of beats away from your maximum. It varies with training status of the individual...

I'd agree with big fellow. LT is the HR sustainable for 20 minutes. As such the more you train the harder you can ride for longer. As I've only been riding for 2 years, you'd expect my LT to be quite a bit off my Max HR.

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"Ride it like you've just stolen it!"

I have checked the HRM at my gym and they are as you say, not accurate.
I was interested in the watts/powers readings that some machines offer. Are the accurate or at least relatively so. Being somewhat vain I just want to know what ballbark I am in. For my needs if I could check my power readings say, once a month that would be fine. I don't really need a powermeter (or the weight) at this time on my bike. Is the gym information useful at all?

I'm no epxert on gym power meters. I'd suggest you get the model details and post them, if your after some feedback from ww experts!

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"Ride it like you've just stolen it!"

Unfortunately, there are LOTS of definitions of LT. I see it more commonly used with an effort sustainable for 60 minutes, not 20. You can be producing lactic acid faster than you can clear it for 20 minutes and still be functioning at the same level(I used to).

And, as said before, there is no set % or relation between LT and Max HR, this is very much influenced by training. The pros have high LTs relative to their HR, recreational riders much lower.

I undrstand that and was hoping that someone that uses a powermeter my perhaps also use one at the gym and notice if they had any value. Thanks for your time

One of the benefits of training with power is that much of its terminology and its methodologies are unambiguous. Instead of things like LT, average powers over a specific period are monitored and trained: 1 min, 5 min, 20 min, 60 min, 2 hour, 4 hour power. Some do refer to "functional threshold," which is roughly equivalent to LT and represents sustainable hour power.

The relationship between time and power is not linear, and is fairly flat after 20 minutes. Aproximate real world numbers for an "OK" nonprofessional are: 1 min - 600 watts, 5 min - 400 watts, 20 min 340 watts, 60 min - 320 watts, 2 hour - 280 watts. So, there is a 60 watt drop-off from 5 to 20 minutes, but only a 60 watt drop off from 20 minutes to two hours, under isopower conditions. It is true that training tends to increase X-axis duration more than Y-axis magnitude.

Are the power meters on gym stationary bikes accurate? I don't think so. In fact, most I have ridden seem to have discrete power bands. If you are curious as to how strong you are, I would time myself on a steep hill, weigh everthing carefully and use an online tool that predicts power from speed, weight and gradient (among other factors).

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John979

Agghh the good old 'lactate threshold' debate!
As I own my own metabolic and fitness assessment company specialising in lactate testing this figure does indeed differ from individual. The fitter you are the higher the lactate threshold and in general the longer you can sustain this effort for. I could hold a true lactate threshold for well over 2 hrs if need be. In fact a 75 mile road race last year I was close to or over my lactate threshold for the majority of the 3 hr race!
For an untrained individual lactate threshold could be very low in comparison to a %tage of maximum heart rate (65 - 75% mhr). But in a trained individual their lactate threshold could be alot higher (75 - 90% mhr). So in theory you can work faster in a better trained athlete.

Lactate threshold is simply the point in which your body accumilates lactate but cannot buffer it and get rid of it whilst working at the same level. So keep going and you will soon run out of steam and get slower. You are still aerobic at this point and burning fat when at lactate threshold. The time able to spend above this zone varies with each athlete but a fitter and stronger athlete will be able to 'suffer' more and go for longer.
One day specialist riders in the 'classics' for instance will probably be able to tolerate huge periods of time above this point especially when attacking and in breakaways.

Lactate threshold is the same as anaerobic threshold. It just gets called different things in different countries.

When your body goes into a complete anaerobic state however this is the effrot where your body will shut down reasonably quickly. But again it varies upon individuals and each athlete. Once completely anaerobic (without oxygen) you burn no body fat. Without your body burning any fat it means your body must source all of it's energy from quick release energy systems (glycogen/sugars/carbs).
Now your body only has around 2500-4500 calories to use from glycogen/carbs but nearly 10 times as much from fat (25'000 - 45'000 calories!). So you can see why it is so importnant to metabolise fats better... to raise lactate threshold... to raise your anaerobic state... so you constantly burn fat when execising at almost every heart rate.

This is why Lance Armstrong is so good at long stage racing... he burns fat to approximately 98% of his max heart rate which means he is still aerobic and burning fat! This also means as a result he will recover quicker! Which is why he can go from stage to stage better recovered than most to be able to race better and more fresher!
Obviously this takes alot of practise and training to get to this level... over 6-7 years in fact!

You need to get tested regularly (3 - 4 times a year) to see how your thresholds change to make the training adaptions neccessary to get faster and fitter!

Mark

You got it a bit wrong, to start glycogen is a pure aerobic energy source. In addition, we all burn fat to 98% or so of our max heart rate.

"better... to raise lactate threshold... to raise your anaerobic state... so you constantly burn fat when execising at almost every heart rate."

You must mean aerobic efficiency? Lance's advantange is that he is more efficient. A very recent paper documents this.

"J Appl Physiol. 2005 Mar 17; [Epub ahead of print] Related Articles,
Links


Improved muscular efficiency displayed as 'Tour de France' champion
matures.

Coyle EF.

Kinesiology and Health Education, The University of Texas at Austin,
Austin, TX, USA.

This case describes the physiological maturation from ages 21-28 y of
the bicyclist who has now become the six-time consecutive
'Grand-Champion' of the 'Tour de France', at ages 27-32 y. Maximal
oxygen uptake (VO2max) in the trained state remained at approximately 6
l/min, lean body weight remained at approximately 70 kg and maximal
heart rate declined from 207 to 200 beats/min. Blood lactate threshold
was typical of competitive cyclists in that it occurred at 76-85%
VO2max, yet maximal blood lactate concentration was remarkably low in
the trained state. It appears that an 8% improvement in muscular
efficiency and thus power production when cycling at a given VO2 is the
characteristic that improved most as this athlete matured from ages
21-28 y. It is noteworthy that at age 25 y this champion developed
advanced cancer , requiring surgeries and chemotherapy. During the
months leading up to each of his 'Tour de France' victories, he reduced
body weight and body fat by 4-7 kg (i.e.; approximately 7%). Therefore,
over the seven year period, an improvement in muscular efficiency and
reduced body fat contributed equally to a remarkable 18% improvement in
his steady-state power per kg body weight when cycling at a given VO2.
(e.g.; 5 l/min). It is hypothesized that the improved muscular
efficiency probably reflects changes in muscle myosin type stimulated
from years of training intensely for 3-6 h on most days."

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John979