Stroke of Genius

I was talking to a friend the other day and she made a comment about attempting to work on her pedal stroke. While most people would find this comment entirely reasonable, innocuous and even commendable, it immediately sent me into a frenzied tirade, as if I was on a mission to keep an innocent pawn from an unspeakably terrible fate. My efforts doubled when she contended that she "had to pull up more" with one of her two legs. Unfortunately I do not think any of the hours I spent putting together tenuous empirical arguments on facebook chat had their intended effect. Not even the logically infallible "I have a perfect pedal stroke. OK well probably pretty close to perfect". That just made me sound like a pompous asshole. (the argument can be made that I am probably pretty close to that as well)

So yesterday, while riding up Gerrard on my fixed CX I felt a sensation while pedalling. I had been riding the whole day clipped in on the same bike (~75km) but decided to wear sneakers on the SPDs for the last errand. On the last stretch of uphill I decided to stand up to pedal my moderate 44/17 gear ratio, and I noticed that on the back-end of my pedal stroke I was lifting my foot gently off of the pedal, having it hover at close range from 7-10 o'clock, and making contact again at the top. "A-ha!" my friend is thinking, "you do pull up on the backside of your stroke" which I had vehemently denied earlier. And I would still disagree as a matter of semantics. I lift up my foot. This can be physically conceived as the difference between running up stairs and running on level ground with 30lb weights strapped to your feet.

Why does this even matter when you are riding? How could it possibly be a bad thing to add more force/energy to the pedal stroke anyway? Well, young grasshopper, first let me explain why I think my pedal stroke is pretty close to perfect, even though I have never had any sort of power testing done; I can climb things. Steep ridiculous things. On a SS. In fact the justification I used for my own perfection was climbing a steep muddy hill at Provincial championships 5/6 laps on my SS while at least half the (geared) competition was bailing to run. In truth this says nothing directly about my pedal stroke. What it does say though is that power was being transferred extremely smoothly and efficiently to the ground, allowing the thin tire to stay tractive even on slick muddy grass.

SO? What does any of my braggary have to do with YOUR pedal stroke? Well is optimally efficient power transfer and smoothness the end to which pedal stroke is a means? I feel like to the majority of people that want to improve their pedal stroke, it probably is. So here is why 'pulling up' on the pedals is a waste of time and energy:

-The definition of a smooth pedal stroke is one with minimal fluctuation of power output at the rear wheel
-Power is transferred via chain and cogs from the crank to the rear wheels
-The crank is driven by your legs
-Constant energy output in the direction of the circles traced by the pedal spindles will lead to constant energy output at the wheel
-Energy output at the crank is obtained by adding the simultaneous vectors of the right and left crankarms
-Generally, the vector of each individual crankarm is strongest on the front/downstroke
-The corresponding simultaneous vector on the opposite crankarm is the back/upstroke
-The hardest part of the pedal stroke at which to tramsmit force from legs to cranks is when one side is at 6 and the other at 12 o'clock

So, add it all up and what do you get? If you are actively pulling up on the back side of your pedal stroke, you are adding energy at a point where it is likely already at its peak, therefore exacerbating any fluctuation in power at the wheel that may already exist. All that is necessary is to lift that foot in the same direction you would be pulling, so that it does not exert a negative force against the powerful downstroke of the opposite foot. The most important part of the pedal stroke to focus on is at the top/bottom of the stroke, where the upstroke becomes down and vice-versa. Developing the ability to smoothly transfer power here will translate most easily into improved speed and smoothness on the bike, especially for mountain biking and CX where traction is a big concern.

Let me finish off by saying that to quote Doom, there are "many ways to fillet feline in these days". Proper care must be taken to develop your stroke in many different positions on the bike; seated balanced, seated forward, standing forward, standing balanced, etc. Depending on fatigue and conditions we tend to alter our pedalling quite a bit, but these same principles can and should be applied throughout most of these circumstances.