Saturday, August 19, 2006

Small changes - great improvements

I've been thinking and critically evaluating my time trial position lately and yesterday I did a lab-test on my position. We evaluated power, technique and efficiency. I wanted to confirm my suspicion that my seat-height was too low.

You might be surprised to hear that the majority of pro cyclists never have any professional fitting done to their race bikes. Most of us probably do just what you do. But after spending a day in the lab yesterday, I can highly recommend spending the extra money on a professional fit.

The reason I suspected my position was off, is that after taking a closer look at my pedaling technique when I time-trial, I have discovered that I pedal slightly toes down. This has in effect "extended" my effective leg-length and since I had been using the generic measurements for determining seat-height, my numbers were off. This nicely illustrates why generic formulas only get you in the ball-park, you also need to take a look at individual differences.

So, this all resulted in raising the seat 1.3 centimeters. Muscles produce more power the longer they are allowed to extend, so not surprisingly my power numbers improved quite substantially.

Eager to test the actual results in the field, I ran through my 16 km TT course today and improved with almost 30 seconds. Needless to say, I'm giddy like a school-girl.

8 Comments:

Blogger Surly Drew said...

Mags,

What kind of wattage do you average for, say, a 40Km TT? How about cadence?

Thanks,

Drew

13:13  
Blogger mags said...

Drew,

I've actually started to put away my power-meter and HRM for all TT efforts, but I usually finish a 40k sub-50 minutes - power is estimated around 400W... give or take a bit. I like to run at least 90 rpm on the candence, ideally 95-100 where that works.

time-trailing is the one thing I've been improving on greatly and where I have most room for further improvement over the next 4-5 years.

Mags

13:49  
Blogger Surly Drew said...

Thanks, appreciate you sharing your data.

Have you tried a lower cadence for TT (in training) and if so, do you see your power numbers dip towards the end of the ride? I am wondering if fatigue would play a part after a certain amount of time spent pushing a heavier gear more slowly, or if this is more attributable to an individual.

As I recall, a guy like Gonchar has always pushed huge gears at lower rpms while guys like Indurain and Armstrong were at their best in the very high end range.

14:27  
Blogger mags said...

Drew,

Yes, I have experimented quite a bit, like most riders. Personally, pushing a bigger gear with a lower candence tend to fatigue my legs much sooner. This happens mostly due to the more extreme contraction of my large muscles in the lower body (allows for less blood-flow through the cappilaries). Also, the makeup of muscle fibers in my lower body favors a slightly higher candence.

It's all individual really.


Mags

14:36  
Anonymous Anonymous said...

Mags,

At the end of the day it does come down to preferences and what works best for the individual. I'm toying with the idea of focusing more on TTing next season just as another goal to shoot for. In my region we really only have two TT races during the season, but I still like the idea of improving it (otherwise why do we train?). At the very least I know the increase in power would help during cyclocross season.

Drew

09:35  
Blogger mags said...

Drew,

Improving your time-trailing would certainly improve your overall performance, since in many ways the TT is the ultimate test of fitness.

Mags

11:22  
Anonymous Anonymous said...

Mags,

Agreed. Because there are only 4 races that actually use it in this area, it's not something that most riders practice regularly. With an inexpensive pair of clip on bars I mean to rectify that for myself.

12:15  
Blogger mags said...

Exactly, clip-ons themselves should give you an extra 3-4 km/hr.

Good luck!

Mags

12:36  

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