PezCycling News - What's Cool In Pro Cycling : Toolbox: Ankling Technique

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Toolbox: Ankling Technique
Since we first learned to ride our bikes, spinning the legs around in circles seem to have been the simplest thing in the world, and many of us don’t give it a second thought. That doesn’t stop scientists from spending endless hours in the lab, however, and in this article we look at the effects of altering ankle angle on cycling efficiency.

Scrape the Mud, Lift that Heel
Think of some of the classic stars of the sport, and what often springs to mind is the ease with which they seem to pedal. Think Coppi or Anquetil and what comes to mind are the elegance and lightness of gazelles as they climbed or tore up time trials. These thoughts revolve around their pedaling action, which translates into an aesthetic fluidity.

Then there are the monster gear mashers – the guys who seem to will their bodies and bikes to success, style or grace be damned. Think Kelly or Santiago Botero, hunched over the bike and cranking massive gears – hard to tell whether they’re torturing the bike or vice versa!

Break down the pedaling action and one key ingredient in the “style” of pedaling seems to be the degree of ankle movement through the 360o. The traditional view is that the ankle should be relatively neutral throughout the entire stroke and neither extremely “toes-down” (plantar-flexed – Lance was a prime example of this) nor “heels-down” (dorsiflexed – Botero is a prime example).

That has been the “traditional” view, a term which just as often means that it has been handed down by Moses and should not be questioned. Never one to leave well enough alone, us lab coat folks are always trying to find what works and what doesn’t when it comes to sport science. I have profiled numerous articles in the past few years on optimal cadence for different applications in cycling, but have not really delved into the actual mechanics of the individual pedal stroke.

Cannon et al.
Over at San Diego State University, Daniel Cannon et al. (1) published a study last month in the European Journal of Applied Physiology comparing the effects of minor levels of dorsiflexion or plantar flexion on pedaling dynamics, muscle activity, and gross efficiency. Some of the basic stats of the research design:

• 11 fit masters cyclists (average 38 y, 61 mL/kg/min VO2max – not shabby!)
• After VO2max determination, subjects were introduced to minor plantar flexion or dorsiflexion pedaling at 80% VO2max workload at a constant cadence of 90 rpm. They were observed and encouraged to maintain the different pedaling styles by both the experimenters and electrogoniometers (fancy electronic devices for measuring angles). No clear info provided on just how long this initial training session lasted.
• Subjects were then asked to practice these different pedaling styles for at least 6 min continuously every ride for at least one week. Again to my annoyance, no info was provided on total practice time of these technique, and “at least one week” is pretty vague!
• The lab test consisted of 6 min pedaling at each technique (normal, plantar, dorsi-flexed) at 80% VO2max workload and 90 rpm, with 15 min rest in between. Electromyography (EMG – recording of electrical signals given off by the muscles) was done on a range of muscles on both the lower and upper leg. Oxygen uptake was measured and gross efficiency calculated as a ratio between energy cost and mechanical power.

Summary of Results
• The plantar flexed (toes down) position was 6.9o and the dorsiflexed (heels down) position was 7.1o from the self-selected. However, the variability between subjects was quite high, suggesting minimal consistency in pedaling technique across the subjects.
• The researchers did not provide any information on whether any of the subjects were naturally already tending towards plantar or dorsiflexion in their normal pedaling.
• Average wattage for 80% VO2max was 250 W, and average cadence 88 rpm.
• No major changes were observed comparing plantar flexed position (toes down) to self-selected.
• The dorsiflexed position resulted in much greater electrical activation of the calf (gastrocnemius) muscle.
• The dorsiflexed position had a higher VO2, and a subsequent lower gross efficiency.

Summary: Putting Rubber onto the Road
There are a few methodological concerns I have with the study that I have outlined above, and also some missing information I would have liked to see. The primary one is of course the very brief time frame for training of a week or so. With something that we do thousands of time every ride, six minutes of training a few times a week is simply not enough time for the body to adapt to any new technique or body position. However, the interesting thing to come from this study is that, while dorsiflexion seems to cost a bit more energy, there doesn’t appear to be a benefit from riding with a more toes-down style.

The main lesson really comes from the major limitation of this study – to become proficient at anything, nothing beats repetition. If you’re going to make any changes in your pedaling, body position, or new equipment, you simply must commit time and effort to it, not make a snap decision based on initial perceptions.

Reference

1. Cannon DT, Kolkhorst FW, and Cipriani DJ. Effect of pedaling technique on muscle activity and cycling efficiency. Eur J Appl Physiol 99: 659-664, 2007.




About Stephen:
Stephen Cheung is an Associate Professor of Kinesiology at Dalhousie University, with a research specialization in the effects of thermal stress on human physiology and performance. He can be reached for comments at stephen@pezcyclingnews.com.

 

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