Wednesday, March 6, 2013

The Science of Speed Part 1 - Watts and Power

In the lead up to this year's Giro and Tour de France, Liam and I are putting together a series of blog posts on the "science of speed."  In these installments, we are exploring the more technical aspects of cycling.  These are the elements that enable cyclists to go from point A to point B faster, stronger and more efficiently.  The focus is on the key areas of power and watts, training and nutrition, aerodynamics and equipment, and mental preparation and race strategy.

A few weeks ago, Liam and I were looking over this list and we started brainstorming ideas, listing contacts we had in the field, and the information that we needed to obtain in order to get a better understanding of each category.  Soon we had an idea map going all over the living room floor.  The design looked a lot like a giant wheel and each area was an important spoke connecting the central hub to the outer circumference of the circle.  When they all started to fit together they formed a perfectly supported wheel --- the foundations of the complete cyclist.  From the living room floor it was time to head out into the real world and see how all this stuff actually worked.  And, just like that, --- the project was born.

Rob explaining some of the concepts of power and speed

We had a late winter training camp planned in Lucca, Italy and, as part of that trip, we had been hoping to get in some riding with our friend Rob Love.  When you meet Rob you can just pick up on his passion for riding bikes --- mountain bikes, road bikes, cyclo-cross and custom motorcycles are just a few of Robs interests.  He also has an incredible amount of information about power and watts and how that applies to bike racing from his work at SRM.  Rob was open and willing to spend a few days with us sharing his knowledge. 

 Liam had several questions about power, mostly coming from an article which he had read about what kind of sustained power it took to be in the top ten in the Tour de France.  There was a figure that was thrown around of a power of 6.2 watts per kilogram of body weight.  This means that if a rider could generate this type of power on the 40 minute climbs in the Tour de France, climbs which often come after 5 hours in the saddle, that they could win the Tour de France or at least be in the top 10.  Last summer when we rode stage 17 of the Tour de France (blog post "To the Pyrenees - Surf's up") we had been in the saddle for around 4 and 1/2 hours when we hit the Port de Bales which is a 19k HC "most difficult climb."  It is the same climb on which Andy Schleck lost his chain when he was battling Alberto Contador in the 2010 Tour de France.  It is exactly the type of climb the article was referring to.  Liam hit this climb, in the words of our friend Sofiane, "comme une fusee" (like a rocket).  Liam blew everyone on the mountain away that day.  There was no way I, Sofiane, or any of the riders that were riding the Tour route that day could keep up with him.  He was pushing over 200 watts average for the climb.  Liam weighed 35 kilos at the time.  We did the math together and figured that Liam was somewhere in the neighborhood of 5.8 watts per kilo.  Will he be able to keep up that ratio as he grows?  Let's say that he will weigh 65 kilos as an adult.  Then, to generate the same power to weight ratio, he would need to be sustaining 377 watts on the same type of climb.  All of a sudden watts, power, and the science of speed became a lot more interesting. 

There was a lot that Liam wanted to know.  He had a basic grasp of what power was and that it could measured and quantified, but beyond that, he didn't really know what watts were and how that applied to riding his bike --- besides the higher the number to faster you go.  When we were talking watts we might as well have been talking about the octane percentage of gasoline --- it didn't mean much out of context.  So the first thing for us to do was learn a new language and terminology of speed and power.  The lesson started as soon as we met up with Rob for a lunch ride in Lucca.  Rob was testing out a customer's power meter to make sure it was properly dialed in.  He took us out on a great loop.  Just a few minutes from the SRM Italian headquarters you are out in the Tuscan hills riding through beautiful olive groves.  This was the coolest classroom ever --- on a bike, riding these incredible roads.  Rob has an incredible depth of knowledge and, at the same time, a gift for sharing it in a passionate and fun way that makes it really interesting.

Rob and Liam looking over the data from our Lucca loop
We learned that power can be used as a language to describe effort and training.  Athletes can use this language to relay information to their coaches about the type of training they are doing.  Power profiles of entire rides can be used to determine strengths and weaknesses.  Perhaps a rider is very strong for the first hour or two, but then starts to see significant power drops thereafter, then they know they should work on building endurance.  We also learned that average power is measured in different time frames ---5 minute, 10 minute, and 20 minute power.  So, if someone says they are doing 500 watts it is important to determine in what context.  Is it 500 watts average for 10 minutes or is it sustained just for 30 seconds in a sprint?  These are different skill sets.  Some athletes can generate huge power for short periods of time.  These are usually the sprinters.  Others can sustain large but not huge power efforts over time.  These are the breakaway and time trial specialists.  As a competitive cyclist, it is important to understand what the strengths and weaknesses of your athletic ability are.  This all plays into race strategy and using the power you have in the most efficient way.  The strongest rider doesn't always win the race, in fact, it is often the smartest rider.

Both Liam and I learned an incredible amount over the course of the ride.  It wasn't all talk, however. We were able to put in some pretty cool efforts on some of the hills, and the winding descents were awesome.  Halfway through the ride we met up with our friend Ben King who is a professional cyclist with Radio Shack Leopard Trek. Ben actually went out of his way to ride with us for a few kilometers.  Just an average ride... only in Lucca!  Ben was getting in some final training before heading up to Belgium for the Three Days of West Flanders race.  After wishing Ben luck for his upcoming Belgian racing, we parted ways and Rob, Liam and I headed back into the hills.  We started cranking out the watts and had a really great final climb with a fun sprint between Rob and Liam at the top.

Rob at work
 After the ride, we headed back to the SRM "villa."  I say villa because that is, in fact, what the headquarters is.  It is located in a beautiful estate on a hill just on the outskirts of Lucca.  Rob had to get back to work, but before he did we were able to go over some of the data from the ride on the power meter Rob was testing.  On that final climb Rob was putting out 907 watts and Liam was most likely in the neighborhood of 450-500 watts.  Cool stuff!  And now it didn't only just sound good, we actually understood better what it meant.  We had learned a whole new language over the course of the ride.

SRM makes power meters which work with the crank drive of the bike.

The next day, Rob set aside some time for Liam and me to swing by SRM and continue with our hands-on lesson of power and watts.  SRM Italy is a service center.  Manufacturing of the power meters takes place in Germany and the US.  Liam had visited SRM Italy last year when we met Rob for the first time, but now he was seeing things with new eyes and with a deeper understanding of what he was looking at. The SRM power meter works in the crank drive of the bicycle.  There are other brands which work with the rear wheel, pedal, etc.., however, SRM was the pioneer in the industry and continues to set the standard in the field.  Rob spent a good deal of time walking us through the "nuts and bolts" of how the whole system works.

SRM power measuring unit with power control monitor

The SRM system works by measuring power with a unit which fits between the crank and the front chain rings of the bicycle.  When you apply force or torque to the pedal the meter is able to record the amount of stress that is put on the unit.  It then, in turn, calculates the cadence or how fast you are turning the pedals.  Watts are then calculated by multiplying the force applied to the pedal by the speed you are applying that force.  Watts = torque value (how much pressure is being applied to the pedal) multiplied by angular velocity (how fast you are turning the pedals).  The information is then transmitted to a handlebar mounted power control which gives the athlete an instantaneous power reading as well as a recording of output for the entire ride.

Rainbow striped world champion version- got to earn this one
 We left SRM with a new ability to quantify effort and power, and we were able to get a better understanding of how that translates into increased speed and smarter racing tactics on a bicycle.  All are important elements in our quest to learn more about the science of speed and better understand the foundations of what it takes to be the complete competitive cyclist.

Liam's favorite color scheme
Just before we said our goodbyes to Rob and SRM, I asked Liam if he had any more questions.  He thought for a second and then said with a smile, "when can I get one?"

Live Strong, Train Safe, and Live Well!

This is Bill and Liam signing out.

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