Biking Hurts Your Junk

Plummeting down a rocky mountain face on a bicycle sounds pretty manly, right? A new study found that—physiologically, at least—it’s just the opposite: Pro mountain bikers have lower testosterone levels than non-cyclists, reports the Journal of Strength and Conditioning Research.

What’s the connection? Researchers speculate that it has to do with a reduction in blood flow to the testes—also called “microtrauma”—due to tight-fitting shorts, constant jostling, and sitting on the perineal region. Less blood means less hormone production, says Ferdinand Frauscher, M.D., a professor of radiology at the University of Innsbruck medical school in Austria.

Studies have shown that these contributors also can elevate levels of sex hormones called gonadal steroids, Frauscher says. High gonadal steroid levels, in turn, impair your brain’s ability to secrete the chemicals responsible for stimulating both sperm-producing and testosterone-producing hormones.


As a recreational rider (less than 3,000 miles per year), you shouldn’t be in any danger of a bike-related testosterone dip, Frauscher says. Recreational riding can actually increase your T-levels, at least temporarily, studies have shown.

Low-key riders aren’t off the hook, though, for microtrauma-induced impotence through nerve and vascular damage. (If your jewels just receded in fear right there, you’re not alone.) The good news: “This is preventable with the right equipment,” Frauscher says. “We recommend soft saddles, padded pants, full suspension bikes, and to get out of the saddle as often as possible.” These measures should reduce the pressure and shaking that hurts your testicles.

Specifically, you want to find a saddle that cushions your pelvis and relieves the surrounding soft tissue, says Jason McMillen, a California high school and USA Cycling certified mountain biking coach. Try a Body Geometry seat by Specialized ($90). The BG saddle sports a “V” cutout that relieves pressure on the internal pudendal arteries to maintain blood flow through your perineum, McMillen explains. Padding on the contact points eliminates most direct nerve pressure.

As for attire, make sure your shorts have a chamois to protect your crotch, but avoid excessive padding or gel packs. “The more padding you have, the more friction you have,” McMillen says. Gel pads may feel fine at first, but they hold heat and will become uncomfortable on long rides.