The Hidden Cost of Daily Cycling?

As merely an inveterate tinkerer on rusty old clunkers, I wouldn't normally presume to weigh-in on such lofty topics, but in the last couple of weeks, I've seen that two of my bike-blogging comrades (Pete of The Bicycle Commuter Trials and Alan of EcoVelo) have fallen victim to tendonitis brought on by daily bicycle commuting. Pete blames his over-zealous and quite sudden conversion to bicycling, while Alan suspects that his saddle height adjustment might have played a role. My bicycle-commuting neighbor has also experienced similar problems with his knees. Whatever the cause, I'm curious to know others' experience with repetitive stress injuries, tendonitis, etc. brought on by daily riding. We all know (or, at least the males among us) about the threat of crushing certain, uh, "necessary" equipment, but what sorts of other injuries have people experienced? Lower back pain? Wrist or elbow issues? Foot/ankle issues?

If you're reading this blog, you're probably already convinced of the health benefits of daily cycling, or cycling for daily transportation, but perhaps we need to be having a more explicit discussion of the physical costs as well. I'd wager that most would agree that "active" injuries like tendonitis are somewhat easier to swallow than the long-term health effects of a sedentary lifestyle (obesity, diabetes, etc.), but I suspect there are folks out there who want or need to start using a bike instead of a car, who might well do serious injury to themselves, thus preventing them from getting back on a bicycle. It's certainly something to be aware of. As our mothers used to say: an ounce of prevention equals a pound of cure.

By the way, here's what Sheldon Brown has to say about bicycling and pain.

Oh, and I found the image here.