I have a friend who has entered the Dave Lloyd Mega Challenge and is training like a man possesed, he has lent me a book about training with a power meter, now is it the cynic in me that thinks if i swap ‘powe meter’ for ‘heart rate monitor’, its just something i read 15 years ago, or are power meters a more accurate/detailed way of training?

Power meters give more instant feedback about what you are doing – with heart rate you can ease off for a bit before it reacts, or it takes a while to catch up when you increase your effort. Generally I find training with power (on a turbo) more intense, as if I’m easing off I know within a second or so.

General concept of training with power is similar though, although there are some books that use different ways of working out training plans based on expended power in a session.

So to answer your question – yes, more accurate and detailed, but not cheap – depends how serious you are. I know a few people who use powertaps now.

I use the SRM system for my road bikes and general training. If you are keen on training in and maintaining a specific exercise zone its great. With hrm you will find variation based on how tired you are supressing the heart rate and most likely you will start too hard as you heart rate plays catchup. After that it will be a case of trying to match heart rate "after the fact" due to the lag. With a power meter you will not have these issues. However for mountain bikes I’m not sure how accurate you need to be with your training zones as riding at a specific power is a lot harder off road