Q : What's the situation with current saddles and how they affect the prostate and other sensitive things down there? I've heard that the safest saddle design will have a center opening and a short nose, and it should be tilted forward to reduce pressure. Is this advice right? How do I find a saddle that fills the bill ? - Robert L.

A: Your concerns are valid, Robert. Given the position of the prostate and the pressure and vibration that many saddles put on the perineum (the soft tissue region in the groin), the prostate and other sensitive body parts can be irritated.

The traditional saddle is shaped like a teardrop. If you look at it from the top, you will see a gradual curvature from the nose to the rear. The trouble with this design is that it closely matches the inner dimensions of the perineum.

On its outer borders, the perineum meets the pubic rami, which are bony parts of the pelvis that connect to the sit bones. If you were to draw a line from one sit bone to the other and include the left and right pubic rami (which meet at the pubic symphysis in the center), you'd have a triangle. When you sit on a traditional saddle, it wedges into that triangle.

If you look at some saddles from behind at eye level, you will notice a crest in the center that drops off toward each side. This dome shape also helps a saddle wedge into the nether regions and push on sensitive arteries, nerves and the prostate. A flat top reduces this tendency.

Some saddle designers have shortened the nose or even removed it in an attempt to prevent it from wedging into where it doesn't belong. They try to make sitting on the saddle the same as sitting on a chair.

The trouble here is that the nose is very helpful -- if not absolutely necessary -- for controlling the bike. Except at very slow speeds, steering is done with the hips, not the handlebar. You need a saddle nose to press against with the inner thighs. Without it you'll be less stable and might even slip off. So the nose is necessary.

A common recommendation is to tilt the saddle down to reduce nose pressure. In my opinion this is simply a response to poor design. It makes a rider slide forward, which increases pressure on the hands, arms and shoulders. The saddle should be kept level from the nose to tail. I recommend a bubble level to make sure of this.

A third way people try to decrease perineal pressure is by cutting a hole in the center of the saddle. Although this may relieve pressure on the prostate (depending on pelvic positioning and the hole location), it removes precious surface area from the saddle/rider interface. The result is increased pressure around the hole, precisely where nerves and arteries are located. So you would be trading one evil for another. You decide which is worse.

The best way to decrease pressure through the region of the prostate is to find a saddle wide enough and flat enough to support the sit bones. It should not have excessive padding that can push up into the perineal region. You want this region to be slightly elevated so it isn't your primary support.

The benefits of a wide, flat rear support surface are negated, however, if you sit forward on the nose. If you have your saddle positioned properly, the nose will be used only to help control the bike.

This is where the teardrop design fails again. The wider the rear of the saddle (good thing), the wider the transition between the rear and the nose (bad thing). This causes the rider to move forward to avoid saddle contact with the inner thighs. When material is reduced from the sides of the transition region, making it narrower, the rider can comfortably sit on the wide rear support surface without any effect on leg movement.

Of course, pelvic positioning figures into all of this. As you rotate your pelvis forward (think lower handlebar and aero position), primary saddle support shifts from the sit bones to the perineum. Conversely, the taller you sit with your pelvis rotated back, the more weight is put where you want it - on the sit bones. A saddle that's wide enough for proper sit-bone support reduces pressure on the perineum well before you're totally upright.

Joshua Cohen, PT, MS did graduate research in ergonomic saddle design at the University of North Carolina and wrote an eBook on the topic, Finding the Perfect Bicycle Seat. He also designed and patented the E3 Form saddle sold through Performance Bicycle.

page mise en ligne par SVP

vélo ski de fond plongeon
Consultez notre ENCYCLOPÉDIE sportive