The way to determine that is to look at the amount of power your body (which is mostly legs with some core muscles) produces when you ride. When I first started training for real, this was a very expensive type of data to access. Usually it was only available to pros and labs. Over the last few years, the costs of these measurement tools have come down along with their weight and the accuracy of their measurements has increased. These various power meters measure how much energy you produce per unit of time (usually in joules per second or watts) by measuring the torque of some rotating part of the bike and the rate or speed at which that part is rotating. This allows you to look both at how hard your cardiovascular system is working and at how much energy you produce to get a more complete picture of how your body is responding to immediate efforts as well as how well it adapts to repeated demands in terms of training "loads" over time.
The power meter I ended up getting (mostly due to cost and portability) is called a Power Tap (the SL model to be precise). This measures power by using a specially built rear wheel hub that has a couple of strain gauges in it to measure the torque the chain exerts on the cassette while also measuring how fast the rear wheel is turning. The nice thing is that I can move the wheel that the hub is built into back and forth between my road bike and my TT bike which allows me to train with power on both.
My last two rides have been used to get the thing and all of it's ancillary electronics working on the road bike. Everything has gone pretty well and the timing was perfect as this is a full recovery week where I do little but spin at low heart rates. This allows me time to play with the position and getting everything to work without feeling like I'm wasting valuable training time. The only problem with the system is that the display unit that sits on my handlebars only had three lines and I want to see a more data than that so for the time being I left my old Polar cyclometer on the bike to give me a little more data.
Today a did a 100 minute ride on my rollers to get a sense of what my average recovery power was and I averaged right at 200 watts which would propel me along the road at around 18 mph (which is about 8 m/s for those who like base metric units). For those who wonder how efficient cycling is, the amount of power used by three average light bulbs can push 185 lbs of weight (80 kg of mass) down the road at a pretty respectable speed. The next two days I'll take the bike out on the road to make sure everything will stand up to the wear and tear of some road rides and get some more base data. On Friday I'll do a set of trainer tests designed to help me set my training levels in terms of my power. These will consist of a ladder exercise where I shift up a gear every minute and keep track of my average power and average heart rate in each step. This will allow me to find my personal power curve, get one estimate of my lactate threshold power and my time to failure after I cross my LT. I'll then do a pair of TT tests where I'll go as hard as I can for ten minutes and find my average HR and power a another estimate of my LT. These will allow me to set my training zones for when I'm out riding ont eh road and I want to do a set of hill intervals or whatnot. Finally, I'll so a series of hard sprint efforts to find my maximum anaerobic power over 5, 10 and 30 second intervals as well as a 1 minute effort. For a data freak like me, it should be cool.
Once I've done that, I'll be able to set my efforts in my next three week training block and then repeat to determine what improvements have occurred. I'm also hoping to pick up a book or two that will help me with this process. I understand Joe Freil has a new version of the Cyclist's Training Bible with info on power and there's another book that's supposed to be the standard for this sort of thing. More to come soon.
Thanks for reading.
