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It's been about 5 years or so since I did any amount of bicycle riding to speak of. Recently, I picked up a mountain bike (Giant Revel 2) and started getting back into riding around some local roads on a semi-regular basis. My goal is to work myself up to at least riding for one hour, three days a week.

However, there's a small problem with this. It seems after about a half-hour on the bike, I begin to experience numbness in my genitals. This usually clears up within a few minutes of standing, off of the bike.

What are some likely causes for this? Are there particular adjustments or modifications I should make to the bicycle or my riding technique to avoid it?

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The design of saddles has been changed over the years to reduce this effect to a considerable degree. If you don't have one already, consider getting a saddle with a cutout in the critical area. These help some people (but not everyone). –  Daniel R Hicks May 11 '12 at 17:38
    
@DanielRHicks: I remember seeing a science TV show in germany years ago, where they tested whether cutouts were good for the prostate or not. They didn't actually look at it directly, but just measured the pressure over the surface of the saddle. Cutouts actually had two points of higher pressure than normal saddles, either side of the cutout (where they're quite sharp), which the show implied was a bad thing. I don't know how that would relate to Iszi's problem, but I'd be cautious about recommending it. –  naught101 May 12 '12 at 2:19
    
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@naught101 -- It depends on who makes the seat. Oddly, Terry, the women's bike people, made the first "anatomical" saddle for men (after they made one for women). Many others have copied the design, some well and some poorly. –  Daniel R Hicks May 12 '12 at 4:17
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5 Answers

up vote 10 down vote accepted

Perineal compression? - http://www.livestrong.com/article/346680-bicycle-seat-nerve-damage/

Basically, you need to change your saddle and/or your bike fit needs modification.

Very valuable information:

This usually clears up within a few minutes of standing, off of the bike.

This is very clearly telling you that either the bike fit or the saddle is entirely wrong. My suggestion? Tweak your bike fit; then, seriously consider a new saddle.

The issue is compression of the perineum which reduces blood flow. Here's some light reading: http://www.medicinenet.com/script/main/art.asp?articlekey=84072

According to Andy Pruitt's Complete Medical Guide for Cyclists the issue is actually more common with recreational cyclists and not racers so much. Apparently, racers tend to be lighter and so aren't supporting so much weight on soft tissue. And also, tend to lift their hips off of the saddle frequently.

Andy Pruitt's key points for solving the problem are making sure that one has an appropriate saddle and especially good bike fit. Generally he recommends that the saddle is at the correct height and usually horizontal. However, for some individuals a slight downward tilt is optimal. An upward tilt is bad news for the perineum.

. wdy

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First thing to come to mind is poor bike fit.Second is are you wearing cycling shorts?If you bought the bike at a local shop see if they offer a fitting service.If they don't see if they will show you how to make some adjustments to the saddle height,forward-aft,and angle so you can experiment to see what makes improvements

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I'm not wearing cycling shorts. I'm probably going to take the bike back to the shop for fit adjustments and maybe a new seat later this week. Thanks. –  Iszi May 11 '12 at 22:18
    
While cycling shorts will help, particularly on longer rides, a properly fit bike and a really good saddle will be fairly comfortable even in street clothes. –  Neil Fein May 12 '12 at 5:55
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As others have suggested, bike fit, padded shorts, anatomical saddle, etc.

When it comes to bike fit, consider the tilt of the saddle: try tilting the nose of the saddle down. If it's above level, or even level, you'll exacerbate nerve compression with the small surface area of the nose. Don't tilt it too far down or as you slip forward you'll constantly be pushing yourself backward on the saddle. Further, examine the position of the saddle relative to the BB. If the saddle is too far back, you'll be sitting on the nose - try moving the saddle forward such that your bum is resting on the wider section of the saddle. Note that saddle position and tilt can affect the saddle height. So write down your saddle height before messing around and readjust afterward if necessary.

Also consider your body position. Are you resting your upper body on your handle bars, or are you supporting it with your core? This will affect hip rotation. The former causes you to roll your hips forward putting more pressure on your perineum. The latter will rotate your hips back relieving pressure on your perineum and resting more on your ischium (I think that's the bone you'd be sitting on.) You can work on your position by keeping your elbows rotated down, relieving weight from your hands, making a conscious effort to use your core, and a conscious effort to feel the effect of hips rotated forward and backward (as far as I can tell, rotating your hips back is done more with your lower abs, similar to thrusting your pelvis forward.)

All this considered, I still get numbness. I compete, I ride a bazillion km/year, I've got padded shorts and an anatomical saddle. Whatever. Likely because I don't support my upper body with my core and roll my hips forward. It's an aggressive position that I like, so I mitigate the issue by occasionally standing - if I'm on flats I switch to a high gear and turn over a low cadence, or I'll just rest my thigh on my saddle and coast (I do this a lot riding in traffic approaching red lights and stop signs.)

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you should probably edit and add that comment to your answer; it's best to keep all the information in the answer –  Nate Koppenhaver May 14 '12 at 2:36
    
Done - not sure on etiquette, but I deleted the (now) redundant comment. –  Duke May 15 '12 at 18:10
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If you're just getting back into riding after a long break, this is normal. It'll still happen for a while - especially on longer and longer rides as you build up your endurance.

There may be some fit issues there, but if you get a saddle with a cutout and your fit looks good (and there's no sharp pain) then you may just need to build up your tolerance a bit.

Cycling shorts definitely help this, as do not overly padded seats. You want your seat to have minimal padding and let your chamois do the padding for you.

Additionally, if you're mashing your pedals instead of spinning you'll most likely experience unnecessary numbness from all the bouncing in the saddle. If you find yourself bouncing, slow down and concentrate on spinning fluidly. There are a lot of threads here on how to improve spin.

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It's interesting that you say "minimal padding" here. I recall that on my previous bike, I had a gel padded seat that was rather comfortable. I'd regularly ride that for trips of a half-hour to an hour or more - once as long as three and a half hours - without any issue. Then again, there is the tolerance factor to be considered as you've mentioned. Regarding spin, are there any particular threads you'd like to recommend? –  Iszi May 11 '12 at 22:11
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Numbness is not normal, and one should stop riding if it's happening. Padding cycling shorts do indeed help, but a saddle with a cutout isn't necessarily required to get rid of the problem. Proper fit is pretty much the only way to cure it. –  Neil Fein May 12 '12 at 5:54
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Gel seats are known for pressing gell into the softer tissue areas away from sit bones. This is actually worse for you than a hard seat. –  Matt Adams May 12 '12 at 13:22
    
@MattAdams - I've heard that the gel actually ends up being pressed away from where you sit, and over time becomes useless. –  Neil Fein May 13 '12 at 4:09
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Read the link that Dan sent; it's frightening! I used to get this 50 years ago, but bikes were were much more rudimentary then, and so were saddles, often made of hard leather. I used to angle it forwards but then always had a re-adjust my sitting position every few hundred yards. These days, saddles are so much better, so get a new and good one. And also wear gel shorts which really help.

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