PHILADELPHIA — In a cluttered gymnasium on North Broad Street, the stench of a lifetime of hard work hung over the tools of a trade that once made Joe Frazier a heavyweight champion and a wealthy celebrity.

On a quiet, sunny Sunday afternoon in this city he adopted, Frazier stayed well beyond the reach of the natural spotlight that beamed through the front window of Joe Frazier’s Gym and swept across an old boxing ring and rows of rusty lockers. Caught in the glow were tables covered with boxing gloves and head gear, and not nearly enough trainer’s tape to hide an old warrior’s wounds.

In a back room beneath a dim bulb, Frazier sat on a sofa and taped his 62-year-old hands for a light workout.

“A sound body keeps a sound mind,” he said.

Then the man known as Smokin’ Joe Frazier, who once formed half of one of the greatest rivalries in sports, rose slowly to his feet. Slightly stooped but still feeling unstoppable, he began to shadow box.