Tuesday, February 24, 2009

Cadence

As I said before, I was disappointed with my initial cycling speed last Friday when I got back on my bike. It felt like I was putting in the same effort as before but my comfortable gear is now 2 cogs less at the back and my resulting speed is a good 3-4mph less. This may not sound a lot but this equates to a reduction of about 13% performance than usual. Baring in mind that my intention is to get my bike speed up to around 25mph for the race, this is a huge deficit before I have even started.

Given the two days of riding that I have done since this disappointing performance, I have been looking at my riding style to see if there is more to it than just a lack of fitness. I should at least be able to ride as fast as before, even if just for a few hundred meters.

The first think I noticed was with my cadence. I have a bike computer is hooked up to my front wheel that will tell me the speed that I am travelling, but it is also hooked up to my crank so that it can measure my cadence, that is for those not bike savvy, the speed that I am peddling. For those that think this measurement is not important when looking to pick up a bike computer, I warn you. It is one of my most important weapons on the road.

Just like a car engine, the human body on a bike has a very similar trait. We all have a power band. This is essentially the speed in which we most efficiently work. Most people would see this as the speed in which they can go on a bike without getting tired, but actually it is the speed we can efficiently move our legs and thus produce the power that drives the bike. The gear we are able to use with this leg speed ultimately affects top speed but for now I want to concentrate on pure revolutions per minute or cadence as it is known.

Again, using the motor engine as an example, as for what it is worth, this is what we are on a bicycle, we need to understand that each engine had different statistics and abilities. A big V8 engine generates lots of power but will not generally rotate as quickly as a small revvy 4 cylinder engine. The maximum power on this latter engine is likely to be much less, but it is still possible to drive quickly using it.

Lance Armstrong and Jan Ullrich are a good example of this. Jan is the big V8. He has big powerful legs and rides at a slightly lower cadence and Lance who is much slimmer and likes to peddle at high cadences.

Like an engine (again), breathing is important. If your engine can breath freely, it is possible to run at much higher speeds. Lance again is famous for his lung capacity which could be one of the reasons why he is able to peddle so fast. Hopefully, working on my fitness will help with this later on.

Anyway, back to me and my issues. I don't have big powerful legs and when looking at the cadence readout on my bike computer I decided that I was peddling at a slower rate than normal. My readout was about 70-75. I was essentially outside of my power band. I was putting in the same effort as before my accident but my peddling was not efficient and as such I was struggling.

If you have ever tried to drive a stick shift (manual) car and tried to pull away in 3rd gear by accident, you will understand this lack of power. As the revs slowly rise, the car starts to spring to life and eventually feels powerful again. The same goes for an automatic. There is a reason for when flooring the accelerator peddle, the car chooses to rev the engine more by changing down a gear or two. It is trying to find the power band for you.

So, with this observation in hand, I tried to experiment a little. I put in a quick effort, without changing my gear, until I was peddling at 85rpm. This instantly felt better, although I was putting in a little more effort to begin with, overall, I felt like my overall effort was less. I was travelling about 2mph faster than before with no perceived effort chance. There of course is a limit to this. As I have said before, gears are an important factor and of course, wind resistance increases the faster you go, so more power is needed, but the main limiting factor is how fast you can move your legs. It should be possible to peddle at over 100rpm but you will soon fall out of the top end of the power band if you go much further.

I found that I can increase my cadence up to 95rpm without feeling like I am putting more effort in. The peddling pressure should in fact feel lighter but the emphasis will switch from your legs to your heart and lungs.

I am finding at any given time that I can balance the emphasis between my legs and organs throughout my ride so that I don't over stress either.

Spinning classes are great for working on this skill. I am pleased with my choice of words there as leg speed is definitely something of a skill that needs to be and should be worked on. Peddling fast without the correct technique can feel awkward if not impossible. Trying to work on a cyclic motion with your peddles rather than a down push or even a push pull motion is a must. This smooth cyclic motion can be extended up to much higher speeds.

Anyway, I am pleased with my instant improvement so the search continues for anything else I can work on other than fitness.

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