The Myth of the Upstroke

Before developing Bythlon's patented technology, we comprehensively researched the biomechanics of the pedal stroke and the benefits of the existing clipless pedal systems using scientific evidence in the form of peer-reviewed published studies.

There are several benefits associated with clipless pedals. First, they allow the cyclists to use bike shoes with rigid soles that would slip off if not mechanically secured. The most recent relevant scientific publication confirms that combining cleats with bike shoes can increase cycling power by up to 25%.

However, the main argument for cleats dates back to the days when cyclists tied their shoes to their pedals with shoe clips and straps. The idea behind that is to generate a 'perfectly round' stroke, pedaling with one leg pushing down while the other is pulling up. 

Most cyclists accept this as a foregone conclusion. And, every novice cyclist will hear the advice to start using cleat pedals to achieve the round pedal stroke. 

So we were in a big surprise when we came across several articles and a video describing 'The Myth of The Upstroke.'

We learned that the presenter of this video, a sport biomechanist and advisor to the United States Olympic Committee, Dr. Jeff Broker, had tested more than a hundred cyclists' pedal strokes from the 1980s onwards. None of these elite and professional cyclists he studied over ten years produced a meaningful upstroke. 

Cyclist do not pull in cirles nor do they truly pull up in the upstroke

He developed an early power force model and called it 'cycling clock diagram.' It is still in use today and frequently cited in publications. It clearly shows that there is no 'pull' in the recovery phase (upstroke).

Cycling Clock Diagram, Pedal strike forces according to Dr. Jeff Broker

He first published his findings with his colleagues Robert Gregor and M. Ryan in 1991 (The biomechanics of cycling). It appeared to them that there is no 'pull' and that the entire aspect of pulling through the upstroke is a myth.

This round stroke concept is simply wrong but remains a very persistent folktale. We believe the reasons that this wrong idea is still around are two general misunderstandings:

First, cycling power analytic diagrams show a positive force on the push-down and a negative force on the upstroke. Cyclists often wrongly assume the negative force to be a pull. Instead, the cyclist can't unweight the leg fast enough when pulling up. The negative force is holding back the pedal!

Pedal Smoothness

The second misunderstanding is the so-called pulling exercises that indeed help to improve pedal stroke efficiency. The reason behind: It makes sense to train to pull up your leg quickly. It helps to leave less weight on the pedal in the upstroke. 

Now, some of these studies are fairly old. So it is important that nothing has changed over time. It was once more confirmed that nobody has power in the upstroke when the Euskaltel-Euskadi pro cycling team provided power meter data to researchers. While not named in the 2016 publication, the great cyclists Mikel Landa, Mikel Nieve, Igor Anton, and Romain Sicard were part of this team.  

At this point, we believe it is fair to say that The Myth of the Upstroke has been debunked by scientists and field data from many thousands' individual cyclists as a popular misconception.