Pedaling Efficiency: Vectors and Motion
While most do not think about the actual vector breakdown involved in the cycling stroke and where the power is applied in detail, when you finally do think about it, things become clearer.

Pedaling... forward, down, back, up?which is it? Circles, ovals, heels up or heels down? With so much advice out there, it is quite possibly one of the most basic movements our legs make, yet so difficult to master to perfection we as cyclists can encounter. This is due to the number of angles of the ankles, thigh, lower leg, and muscles as well as changes of forces involved throughout a pedal stroke. Let us not confuse fast cyclists with efficient or economical cyclists. The ideal cyclist will have both the motor as well as the economy (a low energy cost), and those elements are key for becoming a top notch cyclist or time trialist.

After doing some online research on pedaling efficiency, I ran across an article by Dr. Michele Ferrari which seemed to make some of the best sense I?ve read to date.

I have always tried to trace the perfect circle (except for those few years when Shimano Bio-Pace rings existed,) with my stroke all the way around the imaginary clock we call a crank. Even while attending USAT clinics, and studying for USA Cycling certification, I have run across varied opinions through multiple experts and sources. While most do not think about the actual vector breakdown involved in the cycling stroke and where the power is applied in detail, when you finally do think about it, things become clearer.

There is a vector that is perpendicular to the crank arm as it travels around the ?clock? (chainring/crank). There is also another vector that is virtually parallel to the crank arm as well?which ultimately produces no effective rotary force. The hope is to reduce the negative force vector (the one that is parallel to the crank arm) and between the effective force vector (or perpendicular to the clock/crank). In observing time trial footage of Lance Armstrong, he does in fact, pedal with a ?toes down? style which does in fact eliminate excessive extension of the joints, and as Ferrari says, reduces the force peak for each stroke. More information on force peak.

There are varied opinions and examples separate from Ferrari?s examples of Lance Armstrong as well. The best way to test ?economy? is in a laboratory. After discussing some of the evidence I have found with Neal Henderson, Coordinator of Sport Science at the Boulder Center of Sports Medicine, I learned a thing or two from Neal. He has studied thousands of data examples of world class cyclists from tests done at the center, and did say that pedaling in a toes-down position is not effective for most cyclists. Lance?s position and UCI regulations of specific for/aft bike setups and frame geometry, as well as Lance?s own unique riding style can partly explain this toes down pedal stroke. It is actually more effective for the majority of riders to ?get over? the gear as the toes extend towards the 180 degree position (or 6 o?clock). Dropping the heel slightly to level out of the foot in order to apply the rider?s weight along with activating the gluteus muscles and quads seem to be more effective than the toes down style.

Ineffective motion
Often inefficient motions can be ?fixed? by perfecting drills, and proper bike fit through medical bike fit specialists. One such movement is the common example of knees flailing at the top the pedal stroke. Another falling into this category is the rocking back and forth of the hips?usually caused by seat height being incorrect. Both of these examples will cause dramatic loss in dynamic power output throughout, burning extra energy which could be saved for later on in the run portion of triathlon.

What is effective? Squares, ovals, circles?
The USAT Coaching manual states: ?Square pedaling is common in novices?circles wastes less energy as the recovery leg is lifted just enough to remove some of its weight on the pedal so that less power must be produced in the downstroke to overcome an additional load. By efficiently changing leg direction at the top and bottom of the stroke small amounts of effective power are applied to the cranks again reducing the need for great force production on the downstroke. This means that the rider pedaling in circles wastes less energy than the rider pedaling in squares wastes and therefore reduces the effects of fatigue.? Rotor cranks/oval pedaling, is fairly new and the opinions vary from rider to rider and company to company who manufacture chainrings that the jury is still out on scientific data supporting either side of the argument. In summary,

Some examples of drills to increase pedaling efficiency are:

Single leg pedaling
Higher rpm/cadence sessions
Use a completely opposite approach, such as larger gear/low rpm going uphill, where it will allow you to feel every centimeter of the pedal stroke, and teach you to focus on applying force all the way around the entire 360 degree circle of the stroke.
Fixed gear riding. This will teach your muscles to smooth out the pedal stroke as you learn to stop fighting your bike and eliminate bad habits. Do this on flat terrain.
Written by the D3 Staff.