When I picked up the newspaper this weekend and saw the front page of the Empire News section dominated by pictures of calf roping and cage fighting, I had to stop and wonder about the human condition.

What is it that drives us to risk our health in pursuit of temporary dominance over other people or animals?

I shook my head in disapproval, then popped a couple of ibuprofen for my knotted shoulders, slathered on some ChapStick for my sunburned lips and turned up the heat in the hot tub with hope for relief from lower-back pain.

That's when the light went on over my head. I was tight, sore and blistered for essentially the same reasons as those guys who had spent the weekend wrestling steers and each other at various venues around Sonoma County. While they were riding and roping and punching and kicking, I was pedaling my bicycle 71 miles on a hot and windy day, beating myself up.

Ostensibly, I was helping guide a group of young people on the first leg of a cross-country fundraising ride for an organization called Face AIDS. They needed to get from Ocean Beach in San Francisco across the Golden Gate, through Marin and into Santa Rosa, and I was just shepherding them along the way.

But riding a bike is riding a bike. Every trip is an exercise in risking my health in pursuit of temporary dominance over time and gravity.

To each his own, I suppose.

There are those who see rodeo as animal abuse, and those who abhor the "sport" of fighting as abhorrent violence. They have valid objections. But humans have tested themselves against animals and each other throughout history, and our more "mainstream" sports are really just spruced-up versions of the spectacles provided by gladiators and charioteers of ancient Rome, be that sport the NFL or NASCAR. We have rules and referees, of course, but some fans still give voice to the cheer, "Kill him!"

I gave up competitive sports a long time ago, and not just because I was small and slow. I didn't have the killer instinct that seemed to be required even in rec league basketball and softball games. I was there to have fun, not to prove my manhood. I was out of place.

So I started riding bikes, and found that there, too, is a sport where the instincts that have inhabited our DNA for millennia still drive some cyclists to sprint for first place across city-limit lines, contest imaginary "king of the mountain" points, dial up the intensity when they see another rider on the road ahead.

It seems that we humans just can't help ourselves. Blood-sport is in our blood, even if we don't draw blood doing it.

For me, though, it's not about beating someone to the finish, or beating someone up. It's about testing me against me. Can I improve my time on that familiar 22-mile loop? Can I take this hill in a higher gear? Can I maintain this pedal cadence for another 30 seconds even though I'm completely gassed?

If your idea of thrills includes getting kicked in the face in a boxing ring or stomped into the dirt in a rodeo arena, my relationship to the "killer instinct" probably sounds pretty boring.

But my recovery routine rarely requires more than ibuprofen, ChapStick and a hot tub.

Then it's back out to do it again, and hopefully a little faster and farther this time.

Chris Coursey's blog offers a community commentary and forum, from issues of the day to the ingredients of life in Sonoma County.