This site provides augmented feedback and modeling to facilitate improvement in cycling performance. It is not a bicycle "fit system." While no exact formula exists for perfect riding position and there are many differing opinions about proper bicycle setup, there is a set of characteristics that should be present to attain optimal efficiency or comfort. This "performance bandwidth" is defined here as an acceptable range of interrelated critical kinematic variables that must be accommodated for the cyclist to realize their potential. With this in mind, a set of empirically supported recommendations are presented here to serve as guidelines.
How do we know what will provide optimal performance? There are several ways of knowing, which are listed here in order from most reliable to least:
- Scientific Research: Experimental research and studies published in reputable professionally peer-reviewed sources.
- Data-based: Using accurate and appropriate data as a foundation for drawing conclusions. This is a quasi-science, because it is not peer-reviewed in the traditional way; however, many online communities and professional collaborations exist whereby peers review and agree upon conclusions regarding their data. Use of power data by coaches like Coggan is an example of this.
- Shared Experience: A history of trial-and-error learning by cyclists and coaches yields a practical understanding of what works. Cycling has relied on this method for years, with training techniques developed through years of experience, passed down through generations. Coaches like Carmichael and Friel are examples of the application of this approach (although not exclusively) in their recommendations for training.
- Introspection: Recognizing personal "sensations" and examining past experience with "what works for me." This is more of a trial-and-error approach for an individual.
- Intuition: A "gut" feeling on what is best that is not based on any specific empirical evidence.
While scientific research is most reliable, it is not always applicable to a given situation or cyclist. Furthermore, there is not yet enough research published on some aspects of cycling (or related sports) to draw compelling conclusions. This is one of the major reasons to rely on all of the aforementioned ways of knowing to make decisions for improving cycling efficiency and performance.
WHAT WE KNOW
The following is a list of conclusions I have made from my review of research (for details and support see Annotated Bibliography of Cycling Research). This represents I can confidently say that we know.
- Higher saddle heights result generally in less muscle activity overall.
- Research does not agree upon the effect of high, medium, or low saddle height on metabolic efficiency (VO2, heart rate, lactate levels).
- Using a knee angle measurement to establish saddle height is much more accurate than an inseam or total leg length measurement.
- A knee angle close to 155 degrees is the best for performance and injury prevention. This research supports shared-experience recommendations by others. Carmichael (2003) recommended 145-155 degrees with the pedal at dead bottom center which he defined as the crank arm in line with the seat post (5 o’clock or 150 degrees). The Howard method (Burke, 2002) recommended a 150 degree angle with the ball of the foot on the pedal at 6 o’clock (180 degrees). The Pruitt method (Burke) recommended a range of 145-150 degrees.
- Some research suggests a steeper effective seat tube angle, or sliding forward on the saddle, is more efficient (lower oxygen and more power).
- Some research supports that rolling the body forward into a time trial position does not significantly change the force pattern at the pedal, other than rotating it forward.
- The torso angle does significantly effect muscle activity of the lower body.
Standing vs Seated
- Standing while riding uses more muscle activity and is less efficient metabolically than riding while seated.
- Mild inclines do not have a significant effect on muscle activity while seated.
- Some data suggest that when climbing a steep hill, riders with short legs should move forward on the saddle to make the seat tube angle effectively steeper.
- Single-joint muscles (gluteus maximus, gluteus medius, vastus medialis, vastus lateralis and soleus) provide force only when they can contribute positively (concentrically) while bi-articular muscles (biceps femoris, rectus femoris, gastrocnemius) work to provide equilibrium and coordination during the pedal cycle and possibly transfer of energy.
- Saddle fore/aft and cadence seems to influence the range of angle changes at the ankle (fixed vs supple), but there is not compelling evidence for recommendations on the use of "ankling" for performance benefits.
- Cadence has an effect on muscle activation and timing. Higher cadence results in more muscle activation and activation of each muscle earlier in the pedal cycle. However, there is support for use of high cadence in elite cyclists at high power outputs.
Crank Arm Length
- There is compelling evidence that crank arm length does influence efficiency, but there is less-than-compelling evidence that range of crank arm lengths used in cycling today is enough to make a significant difference.