Questions and Answers on Health

Jim Parker, M.D. and co-founder of Cruzbike, answers some questions about the health aspects of riding regular bicycles. 

Are there really serious health risks to the standard riding position?

Unfortunately, yes. According to numerous recent peer-reviewed medical articles there is a real risk of serious injuries to the perineum in cyclist who ride more than a few hours a week. For example, researchers have found genital numbness may occur in 50% or more of serious male cyclists and erectile dysfunction (ED) in 13 to 24%. Some experts claim the numbers could be higher because many men are too embarrassed to talk about it or refuse to acknowledge cycling as the cause.

What is the perineum?

The perineum (detailed pop-up) is the bottom part of the pelvis from the anus forward. It is made of "soft tissues" such as blood vessels, nerves, fat, and muscles and is not well-suited to weight-bearing.

The Perineum
The diagram at left shows the vessels and nerves a bike saddle may compress as you ride.

As little as three hours per week riding on a bicycle saddle can cause Erectile Dysfunction in men.

Ten or more miles per week can cause genital numbness in women.

Fortunately, you can continue enjoying your cycling without using a saddle.

What kind of injuries can the saddle cause to the perineum?

Bicycle riding on a typical saddle causes erectile dysfunction most likely by damaging the arteries and nerves that run through the perineum. Researchers in Italy and Boston found that the more a person rides, the greater the risk of impotence and loss of libido.
Oxygen levels in the genitals of men have been shown to fall 70% to 80% after only 3 minutes on a standard saddle. The risk of cycling-induced ED is higher for heavier men because they exert more compressive force on the vessels. Researchers have reported patients who developed ED after only one long bike ride. A study of bicycling patroll police officers found significantly decreased penile tumescence and rigidity at nocturnal testing when compared to non-cycling men; and 91% of the bicycle-riding officers experienced groin numbness.

What about women and saddle injuries?

Women are susceptible to the same type of injury to the arteries and nerves that supply blood and sensation to the genitals as men. According to a recent article the Journal of Sexual Medicine, women who bicycled at least 10 miles per week had decreased genital sensation and were more likely to have a history of genital pain than a comparison group of women runners.

What type of mileage can cause this injury?

An analysis of 21 published reports on cycling and ED concluded that more than 3 hours of bicycling per week was an independent relative risk (RR) factor of 1.72 for moderate to severe ED. Researchers in Germany found 19% of cyclists who had a weekly training distance of more than 400 km (248 miles) complained of erectile dysfunction. Another study found a 4.2% rate of ED one week after completing a single cycling event of at least 320 km (198 miles) in men who were free of ED prior to the event.

Don’t the new saddles with “cutouts” solve this problem?

No. The problem is not directly caused by the shape of the saddle. The real culprit is the bicycle’s design that places bodyweight directly over the perineum. This is why bicycle saddles with cutouts do not eliminate the problem. Researchers found that, in fact, some of the cutout designs may actually cause the oxygen level in the genitals to drop even faster because the arteries and nerves run horizontally through the perineum and are subjected to greater pressure where they cross the cutout edges.

My saddle is uncomfortable at first, but then I go numb and it doesn’t bother me. Anything wrong with that?

Yes, terribly wrong. Numbness is your body’s way of telling you its nerves are compressed and at risk of cell death.

What is the solution?

If you must ride a standard bike with a saddle, only use the saddle intermittently and briefly. Unfortunately, this technique is difficult to maintain and transfers the body weight elsewhere, often leading to stress injuries in other areas such as the wrists, neck, shoulders or back. The better solution is to ride a Cruzbike or other recumbent that places the perineum in a forward-facing and non-weight-bearing position while fully supporting your back. For bicycle competitors who are not permitted to ride a Cruzbike recumbent during races because of out-dated UCI rules, they should consider training on a Cruzbike, such as the Silvio, and then racing on their standard road bike to lessen the training hours in the dangerous tuck position which compresses the perineum.

What other ways does the standard riding position increase risk of injury?

I would categorize other bicycle-related injuries as either due to chronic repetitive stress (overuse), or collisions/accidents. The recumbent design of the Cruzbike reduces both types of these injuries. Read on...

Other than injuries to the perineum, what overuse injuries can standard bicycle riding contribute to?

First let me say that bicycle riding is an outstanding low-impact form of exercise with proven cardiovascular benefits. Unfortunately, many, many people give up bicycle riding because of annoying aches and pains in the neck, shoulders, wrists, back, and rear-end.

A study published in the International Journal of Sports Medicine found that 85% of recreational riders had some form of musculoskeletal pain. 49% reported neck pain and 30% reported back pain.

The standard bicycle design makes you choose between riding in a vertical position, which is absolutely the worst aerodynamic position you could possibly be in, versus riding in a tuck position, where your lungs are constricted and your neck is fully extended to allow you to see ahead of you. Both positions often place a lot of weight on the hands and wrists. The recumbent position of the Cruzbike takes weight off the wrists, allows the lungs to fully expand, supports the back, and provides a great forward view without arching the neck … all while in an aerodynamic position.

What about injuries from accidents?

Collisions and accidents are caused by a complex array of factors including the bicycle’s center-of-gravity, visibility to car drivers, the rider’s field-of-view, riding skill, fatigue, head position, foot-to-ground speed, etc. The Cruzbike addresses many of these issues.

The Cruzbike was designed to place the rider eye-to-eye with car drivers, maximizing visibility.
We moved the center-of-gravity slightly lower than on a standard bike to make the Cruzbike more stable in a sudden stop or turn.

The Cruzbike allows the rider to maintain an excellent view of traffic and road hazards without neck fatigue. Many accidents on standard bikes are caused by neck fatigue, which leads to dropping the head down and temporary loss of view of road hazards and traffic.

Neck fatigue leads to "head drop"
... and can be fatal.

Moving at high speed with poor visibility of the road ahead is a common danger of road bikes.

If you’ve spent any time on a standard racing/touring bike, then you’ve experienced staring at the pavement next to the front tire because no one can maintain full neck extension indefinitely. As just one recent example of the dangers of neck fatique on road bikes, the world lost 16 year-old champion cyclist Grant Davis, who died of a massive head injury despite wearing a helmet when he rode "head down" into a trailer parked on the side of the road.

What is foot-to-ground speed?

Sometimes the best safety move is to simply plant your feet on the ground. I have watched many people learn to ride the Cruzbike. It’s very easy and quick to get your feet from the pedals to the ground because you are not perched up high on a saddle. That first 10 minutes or so on a Cruzbike, new riders put their feet down a lot. It’s easy to do and will keep you from falling. As new riders get more comfortable they put their feet down less and less. Before long, they are riding 20 or 30 miles at a time and can’t stop smiling.

What about head position?

If you think about it, as a standard touring bicycle moves forward, the head is the farthest point forward. Therefore the head is likely to be the first point to absorb an impact in the event of a frontal collision. Head injuries are the most common cause of serious injury or death in bicycle accidents. On the Cruzbike, the head is preceded in motion by the feet, legs, and trunk. We recently received a report () from a Cruzbike owner involved in a frontal collision. By his account, we might have expected more serious injuries on a standard bicycle. We believe that as the Cruzbike enters widespread use, data will show a lower rate of accidents and serious injuries when compared with standard bicycles.

If riding a recumbent bicycle like the Cruzbike prevents overuse injuries such as ED, why do so many men still compete in triathlons and other bicycle competitions on standard bicycle saddles?

The UCI “locked-in” the basic form of the racing bicycle in 1934 (see our page for more information), effectively banning recumbents like the Cruzbike. Cycling event organizers may allow you to participate on a Cruzbike, but you will probably be disqualified from official recognition or awards. As the medical evidence mounts about the dangers of the standard bicycle saddle and riding position, I think it’s only a matter of time before sanctioning organizations such as the UCI will permit Cruzbikes and other recumbent bicycles into competitive cycling events for safety and liability reasons, even if it means the breaking of many world records.



“Serious Riders, Your Bicycle Seat May Affect Your Love Life”. The New York Times, October 4, 2005. Sandra Blakeslee.

Genital Sensation and Sexual Function in Women Bicyclists and Runners: Are Your Feet Safer than Your Seat? Marsha K. Guess MD, Kathleen Connell MD, Steven Schrader PhD, Susan Reutman PhD, Andrea Wang MD, Julie LaCombe MD, Christine Toennis PhD, Brian Lowe PhD, Arnold Melman MD, Magdy Mikhail MD (2006) The Journal of Sexual Medicine 3 (6), 1018–1027.

Erectile dysfunction after a long-distance cycling event: associations with bicycle characteristics. J Urol. 2004; 172(2):637-41 (ISSN: 0022-5347; Dettori JR; Koepsell TD; Cummings P; Corman JM; Department of Epidemiology, School of Public Health and Community Medicine, University of Washington and Department of Urology, Virginia Mason Medical Center, Seattle, USA.

The vicious cycling: bicycling related urogenital disorders. Eur Urol. 2005; 47(3):277-86; discussion 286-7(ISSN: 0302-2838)
Leibovitch I ;Mor Y; Department of Urology, Meir Medical Center, Affiliated to Sackler School of Medicine, Tel Aviv University, 59 Tchernichovski st., Kfar Saba, Israel.

Cycling and penile oxygen pressure: the type of saddle matters. Eur Urol. 2002; 41(2):139-43(ISSN: 0302-2838) Schwarzer U ;Sommer F ;Klotz T;Cremer C ;Engelmann U; Department of Urology, University Medical Center of Cologne, Germany.

Impotence and genital numbness in cyclists. Int J Sports Med. 2001; 22(6):410-3(ISSN: 0172-4622); Sommer F; König D; Graft C; Schwarzer U; Bertram C; Klotz T; Engelmann U; Department of Urology, University Medical Center of Cologne, Germany.

US findings in the scrotum of extreme mountain bikers. Radiology. 2001; 219(2):427-31(ISSN: 0033-8419); Frauscher F; Klauser A; Stenzl A; Helweg G; Amort B; zur Nedden D; Department of Radiology II, University Hospital Innsbruck, Austria.

A case of bilateral testicular calcifications in a bicycle motocross rider accompanied by bulbar urethral injury. Hinyokika Kiyo. 2006; 52(5):383-5(ISSN: 0018-1994)
Izumi K; Konaka H; Seto C; Komatsu K; Yokoyama O; Namiki M; The Department of Urology, Kanazawa University School of Medicine.

Effect of bicycle racing saddle design on transcutaneous penile oxygen pressure. J Sports Med Phys Fitness. 2005; 45(3):409-18(ISSN: 0022-4707); Cohen JD; Gross MT; Program in Human Movement Science, Department of Allied Health Sciences, School of Medicine, University of North Carolina, Chapel Hill, NC 27517, USA.

Changes in penile blood flow during cycling--how does one prevent a decreased perfusion? Dtsch Med Wochenschr. 2001; 126(34-35):939-43(ISSN: 0012-0472); Sommer F; Schwarzer U; Graf C; Klotz T; Engelmann U; Klinik und Poliklinik für Urologie der Universität Köln, Germany.

Effect of bicycle saddle designs on the pressure to the perineum of the bicyclist. Med Sci Sports Exerc. 2004; 36(6):1055-62(ISSN: 0195-9131); Lowe BD; Schrader SM; Breitenstein MJ

Effect of changing the saddle angle on the incidence of low back pain in recreational bicyclists. Br J Sports Med. 1999; 33(6):398-400(ISSN: 0306-3674) Salai M; Brosh T; Blankstein A; Oran A ;Chechik A; Department of Orthopedic Surgery A, The Chaim Sheba Medical Center, Tel Hashomer, Israel.

An epidemiological analysis of overuse injuries among recreational cyclists. Int J Sports Med. 1995; 16:201-206. Wilber CA, Holland CJ, Madison RE, Loy SF.

Grant Davis 1989-2006, "Accident Claims One of Cycling's Bright Lights",

Tail Winds, August/September 2006, Vol.9,No.7, pg. 47.

Bicycle riding and erectile dysfunction: an increase in interest (and concern). J Sex Med. 2005; 2(5):596-604 (ISSN: 1743-6095) Huang V ; Munarriz R; Goldstein I; Institute for Sexual Medicine, Department of Urology, Boston University School of Medicine.

Only the Nose Knows: Penile Hemodynamic Study of the Perineum-Saddle Interface in Men with Erectile Dysfunction Utilizing Bicycle Saddles and Seats with and without Nose Extensions September 2005; Ricardo Munarriz MD, Vincent Huang MD, Jayant Uberoi MD, Scott Maitland BA, Terry Payton RN, Irwin Goldstein MD The Journal of Sexual Medicine V.2 (5), 612–619.

Nocturnal Penile Tumescence and Rigidity Testing in Bicycling Patrol Officers; Journal of Andrology, Vol. 23, No. 6, November/December 2002 SCHRADER SM, BREITENSTEIN MJ, CLARK JC, LOWE BD, TURNER TW; From the National Institute for Occupational Safety and Health, Cincinnati, Ohio.

Lief's picture

Not that you need ANY more

Not that you need ANY more reference on this extremely detailed post - but here is an article in the Seattle Times about the same problem.

In fact, it looks like the support for this article came from the very last reference you have listed in your article from the Journal of Andrology.

Have I mentioned how much I heart my Silvio?

cruz2u's picture

To be sure, recumbent bikes

To be sure, recumbent bikes look like a better design.  But what about the neck?  I notice that many photos show the neck curved forward.  If you're riding for long periods of time, its this an issue?  

When you look at a recumbent rider from the front of the bike, it looks like their chest is the main obstacle to aerodynamics.  I wonder why I never see a little mini fairing mounted just in front of the chest, perhaps around the handlebars?  And a tapered luggage area behind the rider.  Many aerodynamics enthusiasts say that what you do behind the obstacle is more important than what you do in front.  The tapered luggage area could also vastly improve the practicality of rercumbents for the average person.  

After all, one of our greatest challenges to lower urban air pollution is to get those people out of their cars.  Being able to transport stuff (mainly food from the grocer to the home) is the main one for most people.  Seeing the long area below the butt going towards the rear of the Cruzbike just makes this all the more interesting.  Of course it needs to be aerodynamically designed but that shouldn't be difficult.  I would think, with the proper design, one could transport an enormous amount of stuff on a Cruzbike.  Add a trailer and now you can move almost as much as a small car when you need to.   

One could also add an ebike motor on the rear wheel!  Just switch it in when you need it.  The battery pack could be mounted anywhere as long as its removable.  Lets go further and mount solar cells on the fairing or luggage areas.  You lose about 30% when using the power from a charged battery verses direct.  So have it switchable so if you want you can power the motor direct from the solar cells.  When you stop, flick that switch and now the cells are recharging your batteries, which you could use in conjunction with the direct power of the solar cells.  Regenerative braking on long hills could improve things a bit more too.  

I see the touring aspects of recumbents particularly interesting.  Adding an aero trailer could result in you being able to bring a lot of stuff camping.  The more stuff you bring, the cheaper it will be as you depend on other people less.  People with small children would especially appreciate this.  Bringing small kids camping can be challenging yet results in thrilling experiences for them that last a lifetime and can positively impact them for decades.

Then there is the aspect of travel.  I see you have a folding bike of sorts.  Brilliant!

 It seems the market for recuments is not only the fitness and leisure crowd but also the utilitarian, ebike, touring and travelling crowds as well!

Choriss's picture

One should include proteins

One should include proteins and vitamins in the diet, and try reducing carbohydrates, if you want to stay fit.  
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Dominick's picture

A recumbent exercise bike is,

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ANNA's picture

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