In my opinion, of all the gadgets out there, those that measure power may be the most beneficial. The Power Tap may set you back $1,000 or more, but if you're serious about your training and you got the cash, its definitely worth it.

http://www.cycle-ops.com/products/powertappro.htm

Has anyone used or seen the new iBike Power Meter. $1000+ isn't ever going to be in my budget and I was wondering if the iBike was good or just junk. Seems like an interesting little machine just from it's marketing material, but you never can tell how things work out in reality.

kddubb

iBike - I looked at it as well - I might be able to convince my wife that it was cost justifiable - but wouldn't be able to do that with a powermeter. The main drawback that I saw with the iBike is that you cannot use it on the trainer. You must be in motion (on the road) for it to function. So, it would be of no use during the off-season and early base training.

I do not understand that for the purposes of training (getting and setting into a given effort) that HR is not as good or better a measure. Yes, to see your progress, you woul dwant to measure power at a given hr. But just going out and maintaining a hr of zone 4 or whatever should get the job done for you.

Besides, all the hot pros and smart dudes have the expensive Power Taps on their bikes. Only the best.

In your post you asked why HR is not as good or a better measure. That is why. Power is more reliable in terms of how your body is actually doing than HR is. Measuring just HR doesn't give the same information. Yes, you need to take the other factors into account, but if you really want a great measurement right now power looks like it might be it. You can't always know "oh, it's 10 degrees warmer out today so I should train at a HR 5 bpm higher". With power, you know what interval to train in for a particular workout at any temperature, etc. There is more information in that than you can get from HR and taking other variables into account.

Training by HR is a method. But HR is too variable, as Kyillee has already pointed out. But if it's all you got, then you go with it. Example: yesterday I could generated my FT (Functional Threshold) watts at an HR that is in my Z3 range, when in fact, it should be in Z4. Does that mean I should have forced my HR up? NO. It means I am VERY fit right now (I'm tapering for an Ironman). My HR to me now is just "interesting" information.

Watts measure the pure effort (which the meters then convert to kilojoules as a measure of calories burned) that you have expended, independent of wind, temperature, terrain, or any particular conditions of your body. This does not mean that there might not be days where it "feels" harder to generate the same watts. But if today my average watts were 180 and I was tired and my HR was up, and 2 days ago my average watts were 180 and I was well rested and my HR was low, I did the EXACT SAME AMOUNT OF WORK BOTH DAYS. Using the power meter, a coach can then specify that the athlete do "X" amount of work in a workout, regardless of what the HR is while producing that amount of work.

Learn--you are confusing training methods with training TOOLS. Whether you train by HR, by pace, or power, the objective of the training is always to raise your lactate threshold, or whatever you like to call it.

So truly if you want to get all scientific about how to know when your LT has gotten higher, then you would draw blood from yourself during and after your workouts and observe the values (Lance Armstrong did hit LT tests, using a power meter, but they also drew blood from him at the end of the test).

But most of us would rather use some sort of approximating tool to determine where our LT is, be it our HR, our pace, RPE, power, what have you. If you are fortunate enough to train under controlled conditions, any of these tools can be sufficient.

The ability to generate watts on the bike is a function of your CV system; but it is also dependent on your ability to apply force to the pedals, which is, in turn, a function of muscular strength. Beginning cyclists are often more limited by the relative weakness of their legs rather than their CV system. If it were just about CV fitness, then you could take any great runner and turn them into a great cyclist quickly. It doesn't work that way.

Learn, if you don't want to use a power meter, then don't. If training by HR on the bike is getting the results you want, then by all means keep doing that

My point would be, based on my own studies and what I have been told, that HR ties in most consistently with what your LT (and other thresholds) are and is the most accurate method of determining how hard you are working (yes, it varies with temprature, recovery, etc - because that also indicates how hard you are working) and what kind of fuel your body is using and what kind of muscles your body is using.

The science on this is changing a lot. Witness this article in the NYT saying that lactic acid is actually fuel for muscles:
http://www.nytimes.com/2006/05/16/health/nutrition/16run.html?_r=2&oref=slogin&oref=slogin