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Tech Report with Lennard Zinn: The science behind the sport

  • By VeloNews.com
  • Published Jan. 23, 2007
  • Updated Sep. 28, 2010 at 4:48 PM EDT

By Lennard Zinn

Ray Browning, emcee and organizer.

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Tuesdays at VeloNews.com usually feature Lennard Zinn’s “Technical Q&A”column, in which VeloNews’ senior technical writer fields questionsfrom you, our readers. But this week, Boulder, Colorado, is playing hostto the first (and hopefully annual) CyclingScience Symposium and Expo, organized by the Serotta InternationalCycling Institute. Yup, it’s a sort of bike geek Woodstock (albeit on a much smaller scale) and we knewexactly where we’d find our friend Lennard. For the next few daysZinn will be attending the seminar and, when he gets some time, even sendingus a few reports along the way. – Editor


Monday marked the opening of the three-day Cycling Science Symposiumand Expo at Boulder’s Hotel Boulderado. Hosted by the Serotta InternationalCycling Institute (SICI), the seminar brought together many of this country’sbest minds in cycling to share ideas and, if all goes as planned, developsome new approaches to the science of this sport.

While kicking the event off with a Sunday evening cocktail party, legendaryframe builder Ben Serotta could hardly contain his enthusiasm for a meetinghe’d been planning for months.

“These are the rock stars of cycling science,” Serotta said. The coolthing was that he wasn’t exaggerating.

Event organizer Ray Browning, Ph.D., a former professional triathleteand top cross-country skier, is now a senior research Instructor at theUniversity of Colorado Health Sciences Center and director of SICI, wasbuoyed by a packed house of eager and paying participants. Browningserved as host and emcee and offered his own presentation on “FunctionalAnatomy for Cyclists.”

Jeff Broker

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Opening the list of speakers Monday was Jeff Broker, Ph.D., former biomechanistfor the U.S. Olympic Committee. Broker currently serves as an assistantprofessor in the biology department at the University of Colorado at ColoradoSprings. Armed with years of pedal-force graphs obtained from ongoing studiesof elite cyclists at the Olympic Training Center in Colorado Springs, Brokerdemonstrated an intimate understanding of how a rider produces power atthis most critical contact point.

Broker separated out the gravitational and inertial components of apedaling force diagram, so that one could really see exactly what was beingproduced and at what cost to the rider. Broker noted that most cyclingcoaches spend a great deal of effort trying to eliminate the downward forcesat bottom dead center part of a pedal stroke. That effort, he explained,is essentially futile, since most of that downward force present thereis non-muscular and takes virtually no energy. Offering an extreme example,Broker suggested that one could knock a rider out cold, clip him into thepedals, tape him down to the saddle and handlebars and crank up the pedalsup to 90rpm. The result, he said, would show similar forces expended atthe bottom of the pedal stroke.

Understanding those non-muscular effects could prevent a coach fromengaging in a counter-productive effort of trying to encourage a riderto eliminate forces which actually come at no energy cost. Indeed, theeffort to eliminate them can actually cost a rider energy and efficiency.

Todd Carver spoke about high-tech bike fitting at the Boulder Centerfor Sports Medicine. He showed BCSM’s high-speed filming and computer analysisof the legs while pedaling.

Kim Blair, founder of the sports innovation group LLC, offered a presentation onaerodynamic research with bikes. He talked about drag and boundary layersand airflow, followed by how tunnel testing is accomplished at MIT andat other tunnels. When he got to the results section, many in the audiencewere taken aback by a water-bottle design from MIT undergraduate student Mark Cote, purportedlyable to save 110 seconds over the course of a 40 kilometer time trial.

Former 7-Eleven team doctor Max Testa, M.D., discussed power outputmeasurement as a training tool for cyclists. Testa now works with EricHeiden, the legendary speed-skater-turned-cyclist, who is now an M.D.,specializing in orthopedics. The two have recently moved from their long-timedigs at the University of California at Davis to the TOSH orthopedic specialtyhospital in Salt Lake City, where the U.S. team for U23 riders recentlyvisited for testing. Testa, also a former researcher at the Mapei CyclingResearch Center, spoke of the importance of identifying talent, as he didat the Mapei center and of recognizing an athlete’s limitations for settingrealistic goals.

Testa said he actually learned some valuable lessons from looking atthe wrong numbers in past years. Before the development of an effectivemethod of measuring power output, riders were often designated as exceptionallytalented based on a single criterion. Indeed, in some cases other criteriamight have shown them have more common, everyday abilities, while others’talents were missed. But power output, said Testa, is the key data pointfor any cyclist hoping to improve. Testa said he likes to tell the storyof an athlete who visited the clinic at Davis to be positioned on her bikeafter tearing her ACL.

Katrina Vogel: Focusing on the interface.

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When Testa saw the kind of power she could put out effortlessly, evenwhile being out of shape and freshly operated upon, he suggested that sheconsider racing bicycles. Last year, Christine Thorburn finished fourthplace in the world championship time trial with only 12 hours per weekof training squeezed around her life as a physician.

The day’s final speaker was Katrina Vogel, a physical therapist at BiosportsNorthwest, and a lecturer at the University of Washington. She spoke abouthow to improve the interface between the pedal and the foot with cleatplacement, cleat shims, orthotics and over-the-counter footbeds.

All in all, it was a great day. The speakers were superb, and the roomwas full with more than 100 paid participants from retail bike shops andthe bike industry. Browning and Serotta both said they want the symposiumto become an annual event, so turnouts like this are a very good sign.

I, for one, hope to be there next year.

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