The morning of last Thanksgiving Day, the moment I stood up from the family room couch, my son began to laugh hard. I asked him what was so funny.

"It's your Old Man Noise," he said, laughing and rolling around on the floor. "That's what."

I took a moment to reflect upon the guttural growl birthed by my half-century-old joints moving in tandem to lift me off the couch. The sound waves sent by my ankles, knees and hips had again massed in my diaphragm, launched themselves, and exploded with a wicked plume from the back of my throat with a mighty "Urrrr-wwuh!"

My son, being only 9, gets a kick out of The Old Man Noise - a term that does not limit itself to men - because it's so foreign to his ears. He and his fellow peeps in the third grade spring off their chairs chirping feathery sounds as if there were no such thing as gravity.

At 52 I've learned to tune out my "Urrrr-wwuh!" because it's incredibly common among my own peeps, a mere soundtrack for the aging process. So when my son hears "Urrrr-wwuh!" it's a shocking noise that helps him understand why his father's generation is known as "The Boomers."

The entire year leading up to my son's laughing fit, I had run, skied, roller-skied, swam and hiked reasonable distances at reasonable speeds, and worked my share around the house. Meanwhile, some of my Boomer-aged friends did nothing more than sit in front of their television sets as they ate through the chips-and-dips bin during three-hour pre-game shows, the three-hour-plus games themselves, and finally the three-hour post-game shows that hyper-analyzed what they had just seen for themselves. No matter. We all make the same Old Man Noise getting up from the couch.

Because it's my nature to rationalize that everything happening to me past age 50 must also be happening to everyone else past age 50, I have concluded that silent sports enthusiasts have met their match. And it is The Old Man Noise. "Urrrr-wwuh!" I'd really like to spy on elite, Boomer-aged ultra-endurance racers to hear what noises they make while getting up from the couch. A not-so-pretty cacophony, I bet.

Have you ever stopped to analyze what has happened to Baby Boomer conversations? Whether we call, meet or e-mail, right off we ask each other about the other's parents, whether they're still alive and, if so, what joint replacement surgery has been scheduled. Talk of children is now replaced with talk of grandchildren, the cars they're driving and when we expect them to graduate from college or get out on parole. At some point our youthful talk of who's hot and who's not and where to go for pitchers of beer has been replaced with talk of toenail fungus and polyps.

And our medicine cabinets. Once upon a time they were nearly empty save for our toothbrushes and paste. Now our cabinets are stuffed with myriad vitamins and herbal concoctions promising us hope for eternal youth throughout our bodies, and prescription medications in case the vitamins and herbs prove false. Then there's the hemorrhoid cream and applicator that we pray our aging vision doesn't mistake for the toothbrush and paste. What really is The Old Man Noise all about, its source and cause? Once again I have undertaken my usual scientific approach in order to answer these questions. (I tilted my head, applied my typical me-focused analysis, and finished by making something up that sounds close to good enough.)

 recalled that my grandparents made The Old Man Noise when they sat down or got up, and they were not silent sporters. I now make that noise and I am a silent sporter. And it's so easy to figure out where the over-50s were sitting in a movie theater when they stand to leave at the end of the show. My conclusion is unavoidable: The Old Man Noise must be both genetic and universal.

he Old Man Noise is the older generations' proclamation of defiance that genetically turns on somewhere in our late 30s to late 40s, and definitely by age 50, depending on genetics. It's an announcement that we're still here, we're staying in the game, and our children can just keep their sticky hands off their inheritance for the foreseeable future. The Old Man Noise therefore is a good sound, a well-earned sound, and a sound that older silent sporters should emit from the moment we rise to wax our skis to the moment we reach to get them out of the rocket box.

To all the Boomers and older folks at the American Birkebeiner starting line this year, be loud and proud of your age. When the starting gun for your wave goes off, make sure that every person who wasn't yet born when Mick Jaeger first sang "what a drag it is getting old" hears your roar of defiance. It will be proof of your strength, power and perseverance against the unwrinkled face of youth. When you first press down on your ski poles, all of you must heave out one mighty, "Urrrr-wwuh!"

I look forward to hearing from you.