For boxers, the chin is the real Achilles heel

The time-worn question of chin is one Steward has had to revisit in one of the rustic old-school training sanctuaries tucked away in the Poconos in Pennsylvania. Steward has been here in the thin mountain air and in the company of deer and squirrels conditioning a gifted, yet vulnerable pupil, Wladimir Klitschko, who faces perhaps the most crucial fight of his once-promising career on September 24.

To the dismay of some members within his camp, Klitschko, 29, will challenge the unbeaten Samuel Peter, 24, the most dangerous contender in the barren heavyweight ranks.

Klitschko, a 1996 Olympic gold medalist for Ukraine once considered the heir apparent to the heavyweight throne, is attempting to silence his critics and prove that he has the heart to take a punch.

The stakes and story lines in this fight could not be clearer. Peter (24-0 with 21 knockouts) is a sometimes sloppy, chase-you-down-and-bang-you-up stalker; another dramatic knockout will put him into prime contention for a title shot. For Klitschko (44-3, 41 knockouts), once deemed the more talented and quicker of the polished Klitschkos — his older brother, Vitali, is the WBC heavyweight champion — the fight is perhaps his breaking point.

‘‘It’s going to be one of those make-’em-break-’em fights for both guys’’, Steward, 60, said in a recent telephone interview. ‘‘A lot of questions are going to be answered.’’

The most important question is the most obvious: Is Klitschko able to take Peter’s punch? Will he show some chin?

It has been more than two years since Corrie Sanders, a flabby, barroom-style left-hander from Australia, knocked down Klitschko four times within five minutes during their fight in Germany. Klitschko was so dazed from the shots, he could hardly stand.

His demons came back to haunt him a year later in Las Vegas against another supposed steppingstone, Lamon Brewster. After surviving a brutal four rounds of the 6-foot-6 Klitschko’s strong right hands, Brewster finally had a chance to tap him on the chin, and Klitschko collapsed to the canvas for another upset.

‘‘It’s not about chin, it’s about heart’’, Brewster said afterward.

If the origins of a good chin are tough to isolate, the anatomy of a knockout can be explained in scientific terms. When a fighter is clipped on the tip of the chin, his head swivels with such force, his brain vibrates inside his skull. That movement stretches nerve tissues in the brain, which then causes a concussion, said Barry Jordan, a longtime ringside doctor with the New York State Athletic Commission.

After conducting medical tests and neurological exams on dozens of boxers, Jordan said fighters who tend to have rugged chins are sometimes those with thicker skulls and necks. Better defensive skills, quicker reflexes and good genes can also be factors, Jordan said.

‘‘A good chin has more to do with genes — a fighter’s genetic predisposition to tolerate punishment’’, he said.

Although the Klitschko brothers have similar physical characteristics and genes, why does the older one seem to have a decent chin and the younger one to have one made of crystal?

That puzzles even 84-year-old Angelo Dundee, who has trained fighters for more than half a century — including one of the best natural chins of them all in Ali. He’s seen fighters take desperate measures to improve their resiliency to a knockout blow. Some fighters build the muscles in their neck; others try push-ups with their chins. None of that works, Dundee said. “You can’t train a chin.”

There are other factors at play, like confidence and stamina. Wladimir Klitschko may have a perfectly fine chin, Dundee said, but a fighter can freeze or become spooked in the ring. He may come to believe his chin is brittle, and that is when he can get in trouble.

Dundee said he liked Peter’s chances against Klitschko. ‘‘This guy is a real banger, a natural banger’’, Dundee said. ‘‘He’ll flatten Klitschko — early.’’

(The New York Times)