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#16 Bericht door eeuwige reiziger »

'n Interessant artikel dat afgelopen maandag in The New York Times verscheen. Ongetwijfeld voor velen onder ons oud nieuws, maar toch nog steeds interessant en actueel.

Mannen weten waarom...! :wink: (maar ook vrouwen, zeker?!)
June 27, 2011
A Release Valve for Cyclists’ Unrelenting Pressure
By JOHN TIERNEY

Before the Tour de France begins this weekend, before the cameras follow all those seemingly virile athletes, let us consider another sort of role model on two wheels.

Robert Brown is an officer in the Seattle Police Department’s bicycle patrol, which lacks the sleek machines and tight jerseys of the Tour de France. But Mr. Brown has something that could be more important to both male and female cyclists: a no-nose saddle.

Like most cyclists, Mr. Brown at first didn’t see any need to switch from the traditional saddle on the mountain bike he’d been riding full time for five years on the force. When researchers at the National Institute for Occupational Safety and Health and Safety offered new noseless saddles intended to prevent erectile dysfunction, he quickly told his supervisor, “No problems here!”

But then, after trying the new saddle, he felt the difference. His weight rested on his pelvic bones instead of the crotch area, which formerly pressed against the saddle’s nose. During his sleep, when he wore a monitor, the measure known as “percent of time erect” increased to 28 percent from 18 percent.

The results made him permanently switch to a no-nose saddle, as did most of the other bike-patrol police officers in Seattle and other cities who took part in the six-month experiment. But they’ve had little luck converting their colleagues, as Mr. Brown complains in the current newsletter of the International Police Mountain Bike Association.

“The subject matter always draws juvenile chuckles,” he writes. “They don’t even listen long to understand what part of a man’s anatomy is being protected here.”

It’s the area of soft tissue called the perineum, and it’s not just a male problem — female cyclists have also reported soreness and numbness in this genital region. But neither *** seems interested in these saddles, and I’m as baffled as Mr. Brown is by their apathy.

I’ve spent much of my journalistic career debunking health scares, but the bike-saddle menace struck me as a no-brainer when I first heard about it. Why, if you had an easy alternative, would you take any risk with that part of the anatomy? Even if you didn’t feel any symptoms, even if you didn’t believe the researchers’ warnings, even if you thought it was perfectly healthy to feel numb during a ride — why not switch just for comfort’s sake? Why go on crushing your crotch?

When I tried a no-nose model for my 16-mile daily commute, it was so much more comfortable that I promptly threw away the old saddle. But over the years I’ve had zero success persuading any other cyclists to switch, even when I quote the painfully succinct warning from Steven Schrader, the reproductive physiologist at Niosh who did the experiment with police officers.

“There’s as much penis inside the body as outside,” Dr. Schrader told me. “When you sit on a regular bike saddle, you’re sitting on your penis.”

More precisely, according to Dr. Schrader’s measurements, you are putting 25 to 40 percent of your body’s weight on the nerves and blood vessels near the surface of the perineum. “That part of the body was never meant to bear pressure,” Dr. Schrader said. “Within a few minutes the blood oxygen levels go down by 80 percent.”

Dr. Schrader has documented the results with the help of a couple of pieces of equipment, the biothesiometer and the Rigiscan.

“The biothesiometer is a device in which the men set their penis into a trough, and it slowly starts to vibrate,” he explained. “They push the button when they can feel the vibration. While it sounds delightful, it’s actually not. The Rigiscan is a machine the men wear at night that grabs the penis about every 15 seconds to see if it’s erect. It’s not as pleasant as it sounds, either.”

In one early study with the Rigiscan, Dr. Schrader found that police officers patrolling on bikes with conventional saddles tended to have shorter erections than did noncyclists. Then, in a 2008 study titled “Cutting Off the Nose to Save the Penis,” he reported the results of having Mr. Brown and the other officers switch to new designs.

Before the study, nearly three-quarters of the officers complained of numbness while riding. After six months, fewer than one-fifth complained. They did better on the biothesiometer test of sensitivity and also reported improved erectile function.

Unlike Mr. Brown, the typical officer in the study showed no improvement in the nighttime Rigiscan measure. A fan of traditional saddles might interpret that as reason not to change saddles, but Dr. Schrader sees it as evidence that some effects of a conventional saddle may be slow, or impossible, to reverse.

In another study, Dr. Marsha Guess and Dr. Kathleen Connell, who are urogynecologists at Yale, found that that more than 60 percent of female cyclists using nosed saddles reported symptoms of genital pain, numbness and tingling. Lab tests recorded lower levels of genital sensation in the cyclists than in a control group of runners. These researchers also report, in a forthcoming paper, that saddles with a “partial cutout” — an indentation or a small opening — may be counterproductive because they increase pressure on a woman’s genital area.

The accumulating evidence has led Niosh to recommend that police officers and other workers on bicycles use a no-nose saddle that puts pressure on the “sit bones.” Examples include the BiSaddle (used by Mr. Brown), the I.S.M. (a favorite of police officers in Chicago), the Hobson Easyseat, the Spiderflex, Ergo’s The Seat, and other models listed at HealthyCycling.org.)

But few cyclists are paying attention. Peter Flax, the editor in chief of Bicycling magazine, told me that he knew of no serious racers who complained about erectile dysfunction, and that problems with numbness could almost always be corrected by adjusting the saddle.

“I suppose there’s a small niche of people for whom a noseless saddle might be a solution,” Mr. Flax said. “But a saddle without a nose has real problems in terms of function. A cyclist can make turns using the weight in the hips against the nose. I just don’t think a noseless saddle is safe in a race.”

Mr. Brown and other police officers insist that they’ve learned to maneuver perfectly well with no-nose saddles. But even if the racers really do get a crucial advantage from the traditional saddle, why is everyone else still using it? People in spin classes don’t have to steer their bikes anywhere, so why are they still sitting on their perineums?

It’s possible the problem isn’t as serious as the researchers believe, but I see other reasons for the indifference. We all tend to underestimate the danger from old-fashioned, familiar technologies, particularly when the effects aren’t immediately obvious. Young athletes focus on victory today, not the future damage to their bodies. And if the winner of the Tour de France doesn’t ride a no-nose saddle, then neither will riders who want to look like him.

“Serious bike riders would be totally embarrassed to show up at a race in a noseless saddle,” Mr. Flax said.

The embarrassment factor extends to bike shops, too, as Jim Bombardier discovered in trying to sell his invention, the BiSaddle. Mr. Bombardier, who lives in Portland, Ore., went to stores armed with scientific papers and diagrams, but no one was interested. One shop owner took a look at his new saddle and summarized the marketing problem:

“This saddle screams out: I’ve got a problem. Who needs that in a bike shop?”

Well, there’s a certain logic to that retail strategy, at least for the short term. But if you’re in it for the long term, if you’d like your customers to keep cycling — and creating new customers — then it pays to protect the perineum.
http://www.nytimes.com/2011/06/28/scien ... .html?_r=1&" onclick="window.open(this.href);return false;

De studie waarnaar in dit artikel verwezen wordt, valt te lezen op

http://onlinelibrary.wiley.com/doi/10.1 ... 867.x/full" onclick="window.open(this.href);return false;
Dagdromend - mijmer ik weg - in de wereld - van het ongrijpbare - is niet alles - binnen handbereik - ben ik op een - eeuwig voortdurende reis
Stormend door het leven met (Versatile009), (Alligt Alleweder042) & (Thorax Tangens)

eeuwige reiziger
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Studie uit 2014

#17 Bericht door eeuwige reiziger »

Een recent grootschalig onderzoek bevestigt nogmaals wat al eerder te lezen stond in het beginbericht van deze draad. Om de zoveel is dat wel onderwerp van onderzoek, maar toch wel merkwaardig dat er maar weinig dokters dan ook in dat verband wijzen op de voordelen van de ligfiets.
Verhoogt fietsen kans op prostaatkanker?
augustus 2014

Mannen van middelbare leeftijd (50+) die meer dan negen uur per week op de fiets zitten, lopen een groter risico op prostaatkanker. Dat blijkt althans uit een onderzoek bij ruim 5.000 Londense fietsers, gepubliceerd in met medisch tijdschrift Journal of Men’s Health.

De mannen die aan het onderzoek deelnamen hadden een gemiddelde leeftijd van net geen 50 en fietsten gemiddeld 6,5 u per week. 8,4% (444 mannen) had de voorbije vijf jaar te kampen met erectiestoornissen, 1,2% (63 mannen) met onvruchtbaarheid en 0,8% (42 mannen) had prostaatkanker. Van de fietsers ouder dan 50 jaar had 1,8% prostaatkanker.

Wanneer de gegevens verder geanalyseerd werden en ook rekening werd gehouden met andere factoren zoals leeftijd, eet- en drinkgewoonten, gewicht, hoge bloeddruk enzovoorts, bleek dat er geen verband bestond tussen het aantal uren fietsen en erectiestoornissen. Fietsen zou ook geen negatieve invloed hebben op de vruchtbaarheid. Maar er bleek, bij de 50-plussers, wel een verband te bestaan tussen het aantal uren dat men fietst en de kans op prostaatkanker. 50-plussers die tussen 3,5 en 8,5 uur per week fietsten, hadden bijna 3 keer meer kans op prostaatkanker, bij mannen die meer dan 8,5 u per week fietsen, was dat ruim zes keer hoger.

De onderzoekers vermoeden dat dit komt door de verhoogde druk op de prostaat, naar benadrukken dat verder onderzoek nodig is om dit te bewijzen. Dit type van onderzoek kan in het beste geval een verband aantonen, maar geen oorzakelijk verband. Volgens de onderzoekers geldt het verhoogde risico op prostaatkanker alleszins niet voor mensen die slechts van en naar hun werk fietsen. Bovendien was de groep 50-plussers met prostaatkanker zeer klein (minder dan 40 mannen), en zijn andere verklaringen mogelijk waarom ze prostaatkanker hebben. Tenslotte benaderukken ze ook dat de vele gezondheidsvoordelen van fietsen ruimschoots opwegen tegen de (mogelijk) licht verhoogde kans op prostaatkanker.

bron: http://online.liebertpub.com/doi/full/1 ... .2014.0012
verschenen op : 28/08/2014 8
http://www.gezondheid.be/index.cfm?fuse ... t_id=16673
Dagdromend - mijmer ik weg - in de wereld - van het ongrijpbare - is niet alles - binnen handbereik - ben ik op een - eeuwig voortdurende reis
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Wouter D
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Re: Overtuig een bukker om ...

#18 Bericht door Wouter D »

verhoogde druk op die plaats lijkt me iets voor kleine bukfietszadelkes :-)
Wens je in te schrijven voor de nieuwsbrief? Hebt u suggesties of vragen? , .... info@ligfietsers.be
help jij ook mee het forum fris en overzichtelijk te houden?

eeuwige reiziger
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Re: Overtuig een bukker om ...

#19 Bericht door eeuwige reiziger »

Alvast een element waar je bij ligfietsen veel minder last van hebt: trillingen die van je pols naar armen en schouders gaan. Onderstaande studie is alvast geen opsteker voor menig wielertoerist die onbekommerd over onze Vlaamse kasseien en betonbanen dendert...

Komt er ooit een studie over de impact van slecht wegdek op ligfietsers?
Cyclists risk nerve damage from uneven street surfaces
Sunday 08 October 2017

CYCLISTS are at risk of permanent nerve damage because of poor road surfaces in Scottish cities, research using a innovative measuring bike has revealed. Vibration caused by uneven streets and cycle paths can cause Hand Arm Vibration Syndrome (Havs).

A study by Edinburgh Napier University found cyclists were at risk of developing the condition after pedalling for as little as 16 minutes on the worst surfaces, such as cobbles.

Dr Mark Taylor, who built an innovative measuring “databike”, plans to devise a cycling vibration route map to help riders avoid the worst stretches and highlight areas for improvement. Taylor, a civil engineer who commutes by bike 12 miles a day, said better surfaces were also crucial to encourage more people to cycle. The databike has a camera, sensors and computer to record vibration levels. He got the idea after realising the need to find a way to record poor surfaces after his seven-year-old daughter fell off her bike when it hit a bump caused by tree roots.

He said: “The minute you get onto a poorly maintained surface you’re getting a substantial duration of vibration exposure that’s being transferred up through your arms and into your shoulders. Continued exposure to such vibration levels over commuter journeys may lead to discomfort and potentially cause harm.” A clinical study is planned to prove the link.

Professor Chris Oliver, a consultant trauma orthopaedic hand surgeon at the Royal Infirmary of Edinburgh who is involved in the research, said: “The vibrations transmitted from some surfaces to cyclists’ hands, arms and wrists can cause Havs. This can equate to significant damage to nerves and blood vessels in the arms. It can include numbness in the fingers and cold can trigger painful finger blanching attacks. Havs can be a disability and can prevent people cycling, especially in our cold winters.

“Cyclists should avoid road surfaces that may expose them to Havs. The damage from Havs can’t be reversed but reducing vibration exposure can help reduce the symptoms.

“Although some cycle paths and roads are riddled with dangerous potholes, it’s continual vibration over time that’s more significant.” Dave du Feu of cycling campaigners Spokes said some cobbles were a particular risk. “It is not just a matter of discomfort, but a cobbled or potholed surface distracts the cyclist’s attention very significantly from the traffic and is a serious road danger,” he said. He said round-topped setts, such as on the High Street in Edinburgh below North Bridge, were “very bad”, but flat-topped ones, like those around the High Street/George IV junction, were “quite acceptable”.

Du Feu said the impact on riders using some bikes, such as those with smaller or narrower wheels, may be ever greater. He said: “The position is likely to be significantly worse for other types of bike, such as the Brompton folding ones which are now very common, particularly for people commuting into the centre of Edinburgh by train.”

Edinburgh City Council transport convener Lesley Macinnes said: “We want to ensure all routes are as well used as possible, so would encourage the public to report any problems and defects they spot on cycle lanes on the council website or by telephone.”

A Glasgow City Council spokeswoman said: “The council is keen to incorporate such data into the assessment of cycle lanes. This method can highlight where investment to improve the condition of the surface is required and where the surface is of the required quality.

“In combination with other data, the implications of this are of smarter investment, the ability to prioritise improvements and to identify where sections are of the required quality. This can result in savings and intelligently targeted investment.

“Whilst vibration for certain surfaces could, with extended continuous exposure, cause harm, in regard to cycle lanes these would be fleeting and are more assigned to the vibration of a 10 mm height drop kerb or a more obvious surface such as a cobbled streets.

“Certain factors within the cyclist’s control such as type of bike being used, tyre width and pressure, even wearing cycling gloves have an effect on how much vibration is transmitted to the rider.”
https://www.scotsman.com/news/transport ... -1-4580875
https://www.napier.ac.uk/research-and-i ... s/databike
Dagdromend - mijmer ik weg - in de wereld - van het ongrijpbare - is niet alles - binnen handbereik - ben ik op een - eeuwig voortdurende reis
Stormend door het leven met (Versatile009), (Alligt Alleweder042) & (Thorax Tangens)

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