HomeNews & FeaturesPart 1: Bike Fitting for Comfort, Efficiency and Reduced Injury

Part 1: Bike Fitting for Comfort, Efficiency and Reduced Injury

Getting ’sized up’ for a bicycle only gets you half way, according to Scott Holz, Global Director for the Body Geometry brand, “Sizing is anything where we are taking measurements of body parts. If you are taking measurements of limbs and applying these to a formula and coming up with the sizes and lengths of things, a totally important process, that is sizing.” Holz offered an example of identical twins who would have an identical bike based on sizing alone.

But what if one twin was fitter and more flexible? What if the other was carrying a hip injury? The rider history, fitness, physiology, and even aspirations on the bike means that the requirements between the two similarly sized riders can be very different… and this is where fitting is important.

Holz explains the fitting concept: “When you think of Body Geometry it is four equal parts; hands, feet, sit and fit. All of the contact points, where we come into contact with the bike, the collection of equipment that we can use at those contact points to make a rider more comfortable, more efficient and reduce their chance of injury”.

Scott Holz was joined in Australia this week by three of the world’s leading medical experts who are responsible for the science, research and product development for the Body Geometry Fit program. This is the first time that the three doctors, the ‘brains’ behind each of the contact points (hands, feet and, of course, the backside), have come together outside of the United States to tell the story about how the solutions have evolved and the science behind each one. Dr. Andy Pruitt, Dr. Roger Minkow and Dr. Kyle Bickel were in Melbourne at the Specialized HQ accompanied by Lucas Hartman and Matt Mangen (saddles) and Australian Body Geometry Fit staff.

Body Geometry Fit Delegation Australia
Dr. Roger Minkow, Dr Kyle Bickel, Dr. Andy Pruitt, Scott Holz, Matt Mangen and Lucas Hartmann


Body Geometry Fit, also known as BG Fit, is a service from the famous bike brand Specialized. Technically it doesn’t limit riders to just this brand, though the BG Fit Centers are found in ‘trained and qualified’ Specialized bike shops. Plus the accessories to address individual rider requirements, such as saddles, gloves and shoes, are created in collaboration with Specialized.

Dr. Minkow and Dr. Pruitt have travelled to Australia on a number of occasions to help educate bike fitters in Australia. You may already be familiar with Andy Pruitt’s Complete Medical Guide for Cyclists which we reviewed on BNA in 2011 and was noted as being “informative, very well written and very readable”.

In the Specialized Bicycle Component University (SBCU) training centre inside the Specialized headquarters in Port Melbourne, Australian cycling media were invited for an engaging presentation with demonstrations on the ‘contact points’ and bike fitting. Of course publicity is important, as Nick Van der Linden of Specialized Australia notes, but the number of ill-fitted cyclists riding in the Amy’s Gran Fondo ride on the weekend just past demonstrates that cyclists are prepared to invest heavily in their bike, their wheels and accessories, but too easily neglect proper bike fitting.


Dr. Roger Minkow: Saddle Design
Historical advertising reveals that at the turn of the century some saddle makers incorporated cut-outs in their saddles for ‘perineal relief’. This topic, however, remained largely ignored over the years. Dr. Minkow revealed that a 1997 article in Bicycling Magazine (US) about erectile dysfunction was the first time in print that this was addressed as a serious medical problem in cycling. And it also cost everyone associated with the article their jobs because of pressure (and denial) within the bicycle industry.

But as a result, Dr. Minkow (who wasn’t in the industry at the time) researched the human anatomy and the arteries around the perineum, made a ‘gaffer tape clad”prototype saddle and sent it to the magazine editor. This in turn led to a phone called from Specialized owner Mike Sinyard who ask him to come in. While the engineering department immediately dismissed the saddle “this looks like bullshit”, Sinyard insisted and rider testing confirmed the benefits of the saddle. The first Body Geometry saddle was released in 1998 and through to 1999 sold 500,000 units and became the most successful saddle on the market to address erectile dysfunction.

Lucas Hartman Saddle Engineer Specialized
Bike adjustment for live pressure mapping by Lucas Hartman (standing) and Stewart Morton (right)


In saddle design, rider feedback is important, however men are often oblivious to numbness and so two tests were developed to provide a quantifiable scientific basis for comparison. The first is pressure mapping to show the (average) distribution of rider pressure on a saddle. Assuming that the saddle has the correct width for the ‘sit bones’, the riders bike position (fitting), style of the saddle, and padding directly influences the pressure and pressure points on the saddle. Live demonstrations by Dr. Minkow, Lucas Hartman and Matt Mangen showed the immediate effect of adjustment in body position; high pressure points on the saddle and poorly distributed pressure which is likely to cause irritation or pain are reduced as the body position on the bike is adjusted.

The second test is intimate; penile blood flow testing is an accurate measure of blood flow in real time. Dr. Minkow’s research suggested that erectile dysfunction was a result of arteries and nerves being compressed against the public bones by traditional bicycle saddles. Measuring the penile blood flow involves gluing a liquid filled ring around the glans (head) of the penis and measuring the oxygen content which provides accurate real time data showing the internal pudendal blood flow as a percentage.

Dr Roger Minkow Body Geometry Fit
Demonstrating the effect of traditional saddles on cyclist penile blood flow

Penile Blood Flow Testing Saddle Design
The tested traditional ‘dome shaped’ saddle reduced blood flow to just 7%


The blood flow testing confirmed that even after just a few minutes riding, the penile blood flow could drop significantly, down to 5%. This data allowed testing of different cut-out shapes and angles to ‘maximise’ rider blood flow. Within the Body Geometry system, the goal is to achieve constant blood flow higher than 75%. Internal and independent testing confirm, as you would expect, that the Body Geometry have the leading saddles blood flow testing.

Stewart Morton Specialized BG Fit Australia
Stewart Morton of BG Fit in Australia with the ‘cut-out’ saddle which improves blood flow


I asked Dr. Minkow about other saddle related symptoms for men such as prostate cancer, “There has been a link between riding a bicycle and increased PSA levels [Prostate-Specific Antigen] but there has never been a link between riding a bike and any kind of cancer. So it definitely can irritate the prostate, but it does not seem like it creates any medical problems,” says Dr. Minkow. “The cut-outs that we have on a Body Geometry saddle are going to relieve prostate pressure because they are cut-out in the middle and you don’t have that dome [of a traditional saddle] that is pushing onto the prostate. All in all, the human pelvis was meant to take the weight on a bicycle, not the soft tissue.”


What about Women’s saddles?
Men are generally ‘insensitive’ in recognising saddle discomfort, noticing first when it is painful. Women however are more aware and sensitive to discomfort. Women who cycle are affected by more problems than men when the saddle and bike fit is poor and this includes numbness, pain, urinary and sexual dysfunction.

Dr. Minkow admits that development of women’s saddles “is long overdue” and while pressure mapping is effective, measuring blood flow is not possible for obvious reasons. His research confirms that the catalyst for women’s saddle problems is the same as the anatomy around the ‘pubic remi’ where arteries and nerves are being constricted the same as men.

Women's Saddle Design
Dr Roger Minkow armed with the women’s Myth saddle


In fact, during research Dr Minkow was unable to find easy answers to a very serious question, “If I tell you where the sit bones are, do you know where vagina is?” None of his medical colleagues were able to provide exact answers; it appeared that women’s sexual anatomy had not been mapped sufficiently and accurately enough to provide the necessary scientific foundation for women’s saddle design. A tip from a physician revealed a book from 1949 by Robert Dickinson called Human Sex Anatomy with millimeter exact documentation of the sexual anatomy of 300 women (and men). Because of the age of the data, a new study was commissioned and confirmed the data was still current.

Armed with this, the women’s Dolce saddle (comfort riders) was created and subsequently the race orientated Myth saddle, which placed the cut-out further forward, matched the changed position. Women’s saddle design is no longer impeded by conservative social conventions, the flow-on effect and popularity of women’s cycling means more investment in women’s specific cycling products.


In part two, Dr. Andy Pruitt (feet) and Dr. Kyle Bickel (hands) share the science behind shoe design and glove design and as part of Body Geometry Fit.

More information on the Body Geometry Fit process online.

Christopher Jones
Christopher Joneshttps://www.bicycles.net.au
Christopher Jones is a recreational cyclist and runs a design agency, Signale. As the driving force behind Bicycles.net.au he has one of each 'types' of bicycles.
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