I can say up front that round pedaling is a myth. For decades, round pedaling was preached as the ultimate goal. In practice, however, the round pedal stroke does not exist, not even remotely. Whereas in the past it was only possible to measure power approximately or estimate it indirectly over the course of a crank revolution, power meters now make it possible to measure power very accurately and visualize it throughout the entire pedal revolution. It turns out that there is a “dead” zone on both sides where no power is generated and where negative forces can even occur during a pedal rotation, counteracting the drive.
Different forces act along the 360-degree rotation of the pedals. These ultimately contribute to the total power output during a pedal rotation. For a smooth pedal stroke, these forces must act positively throughout the entire movement, generating power or energy. To illustrate this, the 360 degrees are usually divided into four sections: push phase, pressure phase, pull phase, and lift phase.
The push phase is what everyone intuitively perceives as the power-generating phase when cycling. This phase generates the most power (around 70 percent) and is crucial for overall performance. By definition, the push phase begins at 45° and ends at 135°. Before and after this, it is almost impossible to generate pressure with the sole of the foot on the pedal. At approximately 90 degrees, the most favorable biomechanical conditions prevail and maximum (tangential) force is achieved. After the push phase, the pull phase begins at 135°. It ends after 225°. The pedal is pulled back and then up with a slightly raised heel. In this phase, between 10 and 20 percent of the power is generated individually. Almost without exception, no energy is generated during the stroke phase. Even professionals usually do not generate any power here. Exceptions are movements such as short sprints while standing. The thrust phase initiates the important pressure phase and is important for the power development of the pressure phase. The phase begins at 315 degrees and ends after 45 degrees. This is where crucial mistakes can be made. If you observe professional cyclists, you will see that in this phase, the heel is only held slightly above the tip of the foot. This allows the pressure phase to begin immediately after the tip has moved forward. Many cyclists make the mistake of lifting their heels too high and pointing the tips of their shoes downwards. This may look “cool” and feel “good,” but it is inefficient. If the heel is raised too much, causing the toe to point downward rather than forward, the pressure phase is initiated too late and/or too little pressure is built up.
Also worth mentioning here are “Q-Rings,” the English abbreviation for oval chainrings. In theory, oval chainrings are supposed to optimize pedal force distribution, which can improve mechanical performance. Even though oval chainrings have been on the market for decades and have been scientifically studied, there is no clear conclusion as to their benefits. This may be due to the individuality of pedaling technique. Some athletes seem to experience an advantage with Q-Rings, while others also experience disadvantages. Here, each athlete should decide for themselves whether to test oval chainrings and see if they can gain a possible advantage.
Two important points are often overlooked when it comes to optimizing pedaling technique—as is also the case with bike fitting:
Firstly, in order to optimize performance, the efficiency of the entire system must be taken into account. Cyclists have both biomechanical and physiological efficiency. Smooth pedaling requires maximum mechanical efficiency so that positive forces are exerted throughout the entire crank rotation. However, for most riders, this is not identical to the best biomechanical efficiency. And even if this were optimized by a round pedaling motion, the overall efficiency would not necessarily be maximized, as there is also a physiological efficiency. Relieving the muscles during the lift phase contributes to a noticeable improvement in overall efficiency. Scientific studies with professional cyclists have shown that the focus should be on maximizing the pressure phase and that the aim for the lift phase should only be to relieve the pressure on the pedal. Overall, it can be said that pedaling technique is highly individual and therefore cannot be improved with standard programs. This is where the second, often overlooked point comes into play.
Secondly, the 3D view of the body and the interaction of the muscle chains of the ENTIRE body are neglected. When pedaling, attention is often paid to a two-dimensional view of the movement. The third dimension, which is virtually perpendicular to the crank and the wheel, is forgotten (unfortunately, this is often the case with many bike fittings). When looking at a cyclist from behind, an asymmetrical posture and/or movement can often be seen. The head is held slightly tilted to one side, and one or both knees move outwards or inwards. If the knees move sideways, this may simply be due to a saddle that is too high or too low, or other poor adjustments on the bike. However, it is important to remember that, unlike a bike, hardly anyone is completely symmetrical. Very often, there is a slight scoliosis of the spine, which manifests itself, for example, in a tilted head posture, asymmetrical hips, and different leg lengths. Attempting to correct three-dimensional inequality with bike fitting is usually doomed to failure. Slight differences in the various parts of the body are not problematic, but should be taken into account in performance analysis. Greater muscular imbalance should be corrected through physical therapy and not through unbalanced, asymmetrical adjustments to the bike and shoes.
Conclusion:
For a long time, the round pedal stroke was considered the ultimate technique. However, when considering the overall interaction of the muscles activated during cycling, activating the muscles in this area can actually have negative effects. The forces generated can counteract and compensate each other. The force exerted is often disproportionate to the power generated, i.e., the energy expended is higher than the energy arriving at the crank. Ultimately, pedaling as smoothly as possible also deprives the muscles of important recovery phases during pedaling. With modern power meters, the power generated can be visualized. In practice, a smooth pedaling motion is virtually impossible and not desirable. It is more important to optimize the pedaling technique so that the pressure phase in particular can be optimized, whereby the thrust phase has a major influence here. Pronounced movements in the ankle joint should be avoided.
Literature:
Grant Petersen, Just Ride: A Radically Practical Guide to Riding Your Bike, Workman Publishing Company, May 2012, ISBN-10: 0761155589, ISBN-13: 978-0761155584
MARTIN HILLEBRECHT / ANSGAR SCHWIRTZ / BJÖRN STAPELFELDT / WOLFGANG STOCKHAUSEN / MARTIN BÜHRLE Trittechnik im Radsport: Der „runde Tritt“ – Mythos oder Realität? PDF: http://spt0010a.sport.uni-oldenburg.de/PDF/DERRUNDETRITT.pdf, Diese Arbeit wurde vom Bundesinstitut für Sportwissenschaft unter der folgenden Projektnummer gefördert: VF0407/06/04/97 abgerufen 01.06.25
Wolfgang Petzke: Muskelleistung und Wirkungsgrad beim Radfahren. Leistung der Gelenkbewegungen – Erklärung zum „runden Tritt“. In: Leistungssport. Nr. 3, 2006, ISSN 0341-7387, S. 47–54. Onlineversion: http://www.caloped.de/LeistungDerGelenkbewegung.pdf abgerufen 01.06.25
Koçak, Fatih & Ertan, Hayri & Pınar, Salih. (2024). Effects of Different Chainring Designs on Cycling Performance: Oval Versus Circular. Sportif Bakis Spor ve Egitim Bilimleri Dergisi. 1. 113-121. 10.33468/sbsebd.378.
Childers WL, Kistenberg RS, Gregor RJ. The biomechanics of cycling with a transtibial amputation: Recommendations for prosthetic design and direction for future research. Prosthet Orthot Int. 2009 Sep;33(3):256-71. doi: 10.1080/03093640903067234. PMID: 19658015.
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