The Moving Crew column in the Dec. 6 Health section incorrectly described Dan Hamner as the physician for the New York Road Runners Club. Hamner is one of 2,500 volunteer medical personnel for the club; the medical director is Lewis G. Maharam. (Published 12/23/2005)

Anyone who ever told you not to beat yourself up hasn't met Dan Hamner, a New York sports medicine physician who promotes a 10-minute-a-day strength training program called "Cave Man Medicine."

Ever skeptical of quickie schemes with slick labels -- to say nothing of cheapo anthropological exploitation of our thick-browed distant ancestors -- I clicked on Hamner's video tutorial expecting the worst. Instead I found an engaging, if oddly creepy, demonstration of the 65-year-old Hamner pounding himself repeatedly on the gut. Hard. With his fists. No hairy suit. No loincloth.

"Striking the body causes muscle contractions," explains Hamner, who is the physician for the New York Runner's Club. Like that other form of self-abuse known as ab crunches, he says, those contractions strengthen muscle and burn fat.

"I had been doing this since I was a kid, and one day someone said, 'Hey, that's what Charles Atlas did!' So I knew I was on to something. Now this and running are my only exercise," Hamner said.

Cave men, Hamner holds, routinely hit themselves to get their circulation cranking and prepare for a hunt. And he knows this how? "It's Darwinian," says he. "We get our DNA from chimps and orangutans and they do it. So it's logical that cavemen did it, too."

Whether this speculation has any truth or not, Hamner seems to have benefited from his regime: In the video, the white-bearded self-flagellator looks almost buff enough to take down a mammoth. (His program is designed to complement a cardio routine of at least 12 miles of walking or jogging per week -- because, we assume, cave men occasionally chose flight over fight.)

"Cave Man Medicine" opens with a Tarzanesque pounding of the upper abs, then the midsection and again on the lower abs, at the top of your pelvic bone. I can report that yes, it hurts to hit yourself in the gut. Still, injury is highly unlikely, Hamner says, because "most of us have built-in mechanisms" against using too much force on ourselves; people on anticoagulants could risk bruising and thus should use light taps.

The next exercise has you lying on your back. Put your fists under your butt, knuckles up. Straighten your legs and raise them 18 inches, then lower them to about five inches off the floor. This works the lower abs, butt, hamstrings and quads. Sitting on your fists forces you to engage you gluteus muscles and gives you an extra 10 to 15 degrees of pivot room, Hamner says. As I lay there knuckling my cheeks, I silently tried to imagine a cave man doing this, but only Fred Flintstone came to mind.

The workout also includes toe raises, chin-ups and one more bit of masochism: pounding on the quads during a "wall sit." "I try to get people back to basics," says Hamner. "You don't need all that gear at the gym."

To progress in the workout, Hamner says to punch harder and hold the static poses for longer. "I hit myself about as hard as a middleweight boxer would," he says. (In case you're wondering, not every exercise involves treating yourself like a punching bag.)

Hamner appears to have nothing to sell -- no book, DVD, podcast or Kevlar chest protector. He's just an old fitness hand with an idea -- if a strangely compelling one -- to share.

The workout took me slightly more than five minutes. And, yes, I felt it, everywhere. Hamner recommends doing it twice a day, every day. View the video, at your peril, at

No chat today, as we are still icing our self-inflicted bruises. E-mail is

-- John Briley

Dan Hamner: Man shares DNA -- and so, he says, natural forms of exercise -- with chimps and orangutans.