The Pelvic Bone

The Pelvis

When sitting normally, the sit bones (red highlighted areas) support the body's weight and have the capability to withstand high pressure. This should also be the case when riding a bicycle.

With an athletic riding position, the perineal area of men and the lower positioned pubic bone arch of women (yellow and green highlighted areas) rest on the saddle.

The well branched out network of nerves and blood vessels of the perineal area reaches from the anus via the genitals to the upper pubic bone arch. On the sides it reaches past the pubic bones. These are capable of carrying a small weight – but a pressure reduction is essential. An even pressure reduction in the perineal area and the pubic bones is achieved through the lowered nose of our SQlab step saddle concept.

The sitting position

Sit Bone Image

When sitting, the sit bones (areas marked in red) serve the purpose of supporting the body’s weight, hence they can endure a high load and pressure. They should also be utilized in this way when riding a bike.

In a dynamic riding position the contact point moves from the tip of the sit bones, forwards along the pubic arch to the pubic bone and the central perineal area. Women, however, typically have a lower pubic arch which can result in higher pressure from the saddle nose when riding in a dynamic riding position. The surface area the rider's weight is resting on is especially critical in a very dynamic and forward riding position and in such a case the rider's weight should not only be supported in the center but also on the pubic bone.

The sit bone and pubic bones both come together from their widest points in a “V” shape. This means the more dynamic the riding position, the narrower the saddle is allowed to be, and should be.

In 2002 SQlab developed a simple equation which uses the distance of the sit bone tips as well as the riding position to calculate the perfect saddle width. Since SQlab's development, this method has been established globally. However, the method may be interpreted slightly differently by different saddle manufacturers and many leave the adjustment equation out all together.

The flexibility of the spine has much less influence on the positioning of the pelvis than is often assumed. Spine and pelvis should remain in a natural position relative to each other and not be forced into a certain position, even if the body is very flexible.

With the SQlab step saddle it is no longer necessary to tilt the pelvis backwards when riding, as the typical pressure zone of the perineal area and pelvis arch no longer pose a problem due to the lowered position of the saddle nose.

The energy which is often required to hold the pelvis upright while the upper body takes a dynamic and forward position while riding a bike is no longer required with the SQlab step saddle. Instead this energy can be used for pedaling and propelling the bike forward.

In addition, there is substantially less load on the spinal discs when riding an SQlab saddle.

Pressure mapping on saddles

How is pressure mapping on a saddle performed?
A pressure mapping foil with sensors is placed on the saddle. As soon as the rider gets on the saddle, the pressure is mapped with approximately 100 pressure mapping sensors and the result is sent to a computer. Thanks to the remote transmitter, the pressure mapping can be performed statically in the lab on a trainer or dynamically in real life on the trail. The pressure distribution is displayed by color: blue represents low pressure, then the pressure rises from turquoise through green, yellow, orange to red.

Bike Saddle Mapping Typical Racing Saddle
The pressure mapping diagram shows an optimal pressure distribution from a medical standpoint on the sit bones (red) and pubic bones (orange/yellow) and almost no pressure in the perineal area.

Typical Gel Curved SaddleBike Saddle Mapping
Shows increased pressure (yellow to red) in the perineal area and in the area of the pubic bone arch.

Bike Saddle Mapping Gel Saddle With Cutout
100px Pressure mapping of a saddle with cut-out shows concernedly high pressure peaks on the sides of the perineal area, where important arteries and nerves are located. In the center the blood is able to flow well, but numbness will still be an issue.

Pressure Mapping of Bike Saddle Types


Numbness of the genitals

SQlab set up

Numbness often appears as a symptom for compressed nerves and/or reduced blood flow in the perineal area.

Special nerves and blood vessels in the perineal area of men are responsible for erection. If the blood supply to these is reduced or they are compressed for any extended period of time, this can lead to reduced sexual performance. This process is reversible, as after a longer period off the bike this process is usually reversed and normal sexual performance returns.

Caution! This problem can become chronic. Numbness is an alarm signal! Those who listen to their body can minimize the risks so that the positive effects of bike training prevail. Cycling is a fantastic heart-circulation-training and hence can improve sexual performance.

What has science got to say to it all?
Scientific studies have shown that athletes generally suffer less from erectile dysfunction (ED) than non-athletes. Results of several research studies lead to the conclusion that approximately 6 – 10% of all men between 30 and 50 years of age suffer from moderate to severe ED. A very meaningful research study among athletes has shown that 1.1% of runners suffer from moderate to severe ED, 2% of swimmers and 4.2% of cyclists. Assuming that the positive effects of cycling are at least comparable to those of running, 3.1% of cyclists experience impairment instead of an improvement. With rising age however, it decreases disproportionately. It therefore makes sense to partake in sports activities, especially cycling, but with care to use an anatomically correct saddle. It would be a real shame if the positive effects of cycling were nullified through the use of an incorrect saddle.
Source: (Huang V, Munarriz R, Goldstein I., Institute for Sexual Medicine, Department of Urology, Boston University School of Medicine, 720 Harrison Avenue, Boston, MA 02118, USA., Sep. 2005)

Measure the sit bone distance in order to ensure your saddle is not too narrow. The SQlab step saddle concept distributes the body weight according to medical principles. A maximized seating area on the saddle ensures the sit bones can bear the majority of the body weight.

General tips on numbness:

  • Ride in a more upright position
  • Ride out of the saddle more often
  • Avoid riding with a heavy backpack
  • More pedal pressure reduces the pressure from the saddle
  • Reduce body weight – reduces pressure from the saddle
  • Use a thinner saddle padding
  • Sit as far back as possible on the widest part of the saddle
  • Tilt the front of the saddle down slightly
  • Optimize geometry (SQlab recommends Body Scanning CRM) 

More space on the nose of the saddle the better

Numbness occurs as nerves are compressed and/or are receiving reduced blood flow in the perineum area. The corresponding body part cannot be felt correctly and is perceived as numb. The problem can become chronic.

Numbness is a sign for concern! The stepped design of SQlab saddles distributes body weight in the correct places, mainly the sit bones, while reducing pressure on soft tissue in the perineum area. The MaxContact® technology, with optimal saddle nose design, offers a maximum contact area while not inhibiting pedaling efficiency.

The Difference Between Men & Women Bike Saddle Geometry

Saddle Geometry of Men and WomenThe pelvis of men and women differ due to the fact that a woman’s pelvis needs to be able to facilitate giving birth. For SQlab however, the contact to the saddle is of interest – and here, the difference is less than often assumed.

The method SQlab has developed to measure sit bone distance has provided interesting findings. Meaningful statistics about the sit bone distance as relevant for a bicycle saddle were previously not available. Internet research on the topic of sit bones yields information about German Shepherds, but barely any information about humans. The statistics SQlab has developed over the years show that the sit bone distance in men lies between 6 cm and 16 cm and in women between 9 cm and 17 cm.

The previously rarely considered anatomical difference of women’s generally lower positioned pubic bone arch often leads to high pressure experienced on the saddle nose when riding a bike. There are many women with a narrow sit bone distance and many men with a large sit bone distance. Different saddles for men and women are no longer needed with the SQlab concept. The lowered saddle nose relieves the typical problem zone of men, the perineal area and about 2 cm further forward the pressure point between the female pubic bone and saddle nose. (The difference between men and women with only 2 cm is much smaller than often assumed.)

Research about women specific saddles.
The German Sport University Cologne has performed research on women with pressure mapping and two different saddle types (Gel saddle and saddle with cut-out) in various different riding positions. None of the tested saddles showed a satisfactory relief in the area of the pubic bone arch / saddle nose. The results concur with SQlab's research performed in the SQ-lab. The SQlab saddle width system in combination with the lowered saddle nose of the SQlab step saddle is hence not only first choice for men, but also relieves the typical pressure points women experience. This leads to the conclusion that women specific saddles based on a different shape and seating position of men and women are no longer necessary.

SQLab Step Technology for Women's Bike Saddles

The bike saddle with a hole distributes pressure over a smaller surface, with high pressure at the sides of the hole.

Therefore not only did the saddle with a hole not change the amount of pressure on the central part of the saddle, it centralized it in an area which can potentially cut blood and lymphatic supply to a woman’s outer genitalia. On the control saddle high pressures can occur on the sides of the hole, therefore compressing parts of the Labia Majora (shown in red). In the central part of the saddle, the Labia Majora gets caught in the middle of the hole. Compression over a limited portion at the center of each Labium could damage the skin and the lymphatic system, compress the nerves or cut blood supply to the rest of the Labium falling in the middle of the hole. This does not happen on the flat saddle with gel.

Cut-out and narrower saddles negatively effect saddle pressures in female cyclists. Effects of saddle design on pudendal nerve sensory function were not apparent in this cross-sectional analysis. Longitudinal studies evaluating the long-term effects of saddle pressure on the integrity of the pudendal nerve, pelvic floor and sexual function are warranted.

Solutions: The SQlab step saddle with lowered saddle nose reduces the pressure evenly. Tilting the saddle forward achieves the same outcome – the rider, however, will slide forward into the narrow part of the saddle. A more upright riding position lifts the pubic bone.


The Spine and Saddles

The Spine Alignment on a BikeThe Human Gait
The description of the human gait has always been a fascinating topic. The amount of available information is huge and numerous studies have analyzed this topic in great detail. One thing is for sure, evolution has provided us with an ingenious system with which, if it is not damaged, we can move forward with ease. The important basis however, are three muscle loops: two placed longitudinally and one diagonally. With their fascia and tendon systems they have the ability to take up and store energy.

The thoracolumbar fascia links the contralateral shoulder muscles with the gluteal muscles, which stretch all the way down to the lower leg and foot. In short, on every stride, the muscle loop system is stretched, energy is stored, and again released in the next stride. Throughout this process, we hardly need to add any muscle energy. If we, for example, just stroll along in an uncoordinated manner, the loops are not supplied with sufficient energy. This could be a reason as to why many of us experience going shopping as exhausting. In the search of the unbelievable running speed of Usain Bolt (1), researchers have focused on the long tendons which are able to catapult him forwards with incredible speed when tensioned.

Why is this of importance for cycling?
Only a biomechanically correct gait makes use of the system of contralateral interconnection. To provide for this, a correct rocking movement of the pelvis is absolutely essential. This horizontal movement is achieved with our SQlab active saddle technology.

With a fixed pelvis position in the sagittal plane when on a bike, pain in the lower lumbar spine, the pelvis and the hips are to be expected, as our musculoskeletal system is not designed for this movement.

The Spinal Discs
The spinal discs consist of an outer annulus fibrosis and a gelatine-like core. The core has the ability to bind water and through the swelling pressure it provides an excellent buffer function.

Excessive Physical Load
Our spinal discs have no blood supply. They feed by diffusion and the principle of a sponge. A mix of alternating load and relief keeps them alive. Unfavorable continuous high loads however cause the cells to die.

(1) Usain Bolt (* 21. August 1986 in Trelawney Parish) is a Jamaican sprinter
triple Olympic champion and world record holder in 100 and 200 m sprints.
With a world record time of 9.58 seconds (August 2010) he is the only human to have
covered the 100 meter distance in under 9.6 seconds.
He stands 1.95 m tall and has a competition weight of 86 kg.

Painful Sit Bones While Riding A Bike

Painful Sit Bones While Riding a BikeThe larger the area, the lower the pressure. This physics law implies an advantage for the SQlab step saddle concept. The area does not - like with other ergonomic saddles - need to be reduced in a contra-productive manner with holes and cut-outs.

What is the meaning of this with regards to a bicycle saddle?

Pressure = pain causing magnitude, which should be as small as possible
Force = magnitude determined by body mass and gravitational acceleration
Area = usable surface area of the saddle and cyclist

A Too Soft Saddle

Too Soft of a Bicycle Saddle 

A too soft saddle usually becomes very uncomfortable after approximately 30 – 45 minutes on the bike.
The sit bones sink in so far  that sensitive soft tissue such as muscle and tendons are aggravated. After approximately 30 – 40 minutes a dull deep pressing pain sets in.

The sinking in of the sit bones also causes the perineal area in men and the lower positioned pubic bone arch in women to be subjected to higher pressure. Specifically soft padding will effectively stop the blood flow.

It is rare that the padding is so soft that the saddle shell causes the discomfort.

Familiarization Of The Sit Bones

The sit bones are capable of getting used to a high pressure load and the discomfort will reduce. At the beginning of the season, or when switching to a new unfamiliar saddle shape, pain and discomfort in the sit bones is normal. Familiarization with a new saddle can take approximately 5 to 6 rides. At least two days of rest should be scheduled between the initial rides to give the already sensitive muscles and tendons time to respond. SQlab lists the hardness of the padding material on the saddle. SQlab has developed a measurement unit called SQ Shore, which takes into account the combination of both cover and padding materials.

Pressure Of The Sit Bones

Pressure of the Sit Bones when CyclingThis is a problem primarily experienced by women as the female tailbone is more flexible and commonly also more sensitive than the male tailbone. When in a very upright position, the tailbone can be very close to the saddle. In combination with a too soft or too narrow saddle this can lead to discomfort and pain. The pelvis is held together by ligaments. When there is tension in the pelvis, these ligaments can exert a high strain to the tailbone. Riding completely tension-free is made possible by the 600 active.

Prostate problems

 Prostate Problems on a Bicycle

It's important to reduce the pressure to the prostate as much as possible.

If you experience a prostate inflammation it is important to prevent any pressure to the perineal area. If you have had prostate surgery cycling is only recommended after a certain time – if at all – and with a saddle like the SQlab 600 active.

Interesting facts: The prostate is a gland which often grows for the entire lifetime. This is why the older men become the more likely they are to have issues with it.

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