'Go home and hug your mother!"

That gruffly stated order upon leaving the Jack Costello Boxing Club is a standard in the Irish-dominated Tacony neighborhood where 25 to 50 sweaty young boxers, many of them teenagers, turn up on weekday evenings for training, sparring, and maybe even getting their lives together.

Or, sometimes not.

The trainers watch for injuries in the ring but also keep an eye out for the less-visible ones, the ones the boxers may already have.

"I don't know what's so terrible that a 15-year-old would commit suicide," said Patrick Costello, 55, one of several volunteers who run the place, "but he did." He won't say much more about the teenager who used to train there regularly, but the memory of him reminds Costello why he's there.

Though more altruistic than some, the Costello club is one of a handful of private Philadelphia gyms - operating independently in blue-collar neighborhoods around the city - with common purposes that allow this retro sport to address all manner of modern ills.

Kids who have grown up on video games - and who no longer have phys-ed programs in their public schools - learn what it is to do more than four push-ups in a row. Or to make eye contact with another human being. Or take orders from the coach on the sideline. Or learn self-defense without firearms.

Some gyms practice tougher love than others, such as when kids arrive looking stoned. At Rosati's Gym, above Mickey's Auto Repair at 1937 S. Chadwick St., where many train for the annual Golden Gloves boxing matches, they are simply told to come back when sober.

Zahir Justice, who built and runs FastLane Boxing Gym at Jefferson Street and Lancaster Avenue, welcomes the obese and even the mildly autistic by using more of a light touch.

"You don't want to lose them," he says. "You have to let them know you care."

His own story: "I used to do amateur boxing - ages 14 to 16. My coach died and I lost interest. I let the streets get to me . . . for 25 years . . . doing bad things. I don't want what happened to me to happen to them."

The Costellos - the extended family keeps the gym going four nights a week - are connected with a network of treatment centers, halfway houses, and 12-step meetings.

"At one point, a judge in Philadelphia sentenced kids here for community service," said Patrick Costello. "When you look a kid in the eyeballs and tell them you know what they're going through . . . they're not alone and know you're telling them the truth."

Of course, some just want to box. And they do. Boxing lessons can be had all over Philadelphia, but with lower prices - often, whatever you can afford to pay - these gyms have a neighborhood crowd that temporarily booms with each Rocky Balboa film. Curiously, the recent Creed prompted an influx of women.

"It hasn't caught on like Jazzercise," says Gregory Sirb, executive director of the Pennsylvania State Athletic Commission in Harrisburg. "This is truly an inner-city sport, much more than basketball. It teaches kids discipline and taking better care of themselves . . . but this is a very rough sport." Even with protective headgear.

Boxing proponents won't let it go. Mickey Rosati Jr. gave up fighting at 19 (and his 80-something father, Mickey Sr., is in the Pennsylvania Boxing Hall of Fame), he keeps his gym going, though he could rent out the space for $1,000 a month. It's a culture.

It's also family, says Costello regular Dominique Collette, 29, who punches bags while her son, Gio, watches. "When I stop going to the gym," she said, "I get depressed and have bad anxiety."

Still, the clubs have no frills. Forget air-conditioning. Decor is limited to boxing posters that wrinkle in the humidity. An American flag is standard.

Celebrities drop in. While recovering from shoulder surgery, heavyweight Joey "The Tank" Dawejko, 26, offered informal coaching at Costello. Nafis Ricks, 28, a former college basketball star who has played pro ball in Brazil and Finland, is doing boxing training for the second consecutive summer at FastLane because it ups his game.

But from Chicago to Louisville, boxing gyms are on a slippery slope. The Costello gym, which makes its expenses entirely at an annual beer-and-beef fund-raiser, had a sweetheart deal renting the third floor of the 1890s Tacony Saving Fund Safe Deposit Title & Trust Co. When the previous owner was chasing a runaway dumpster on one of Tacony's hillier streets, a member of the Costello clan stepped in to help.

From that association, the club opened in 1996, dedicated to the family's patriarch, Jack, who died in 1989 and who was both a boxing coach and certified addictions counselor. But with the building now sold, the Costellos are setting up on a different floor to make way for a new recording studio and wonder how well that will work.

At FastLane, Justice, who works as a part-time security guard, leased the second floor of the Jefferson Avenue building - a former after-hours club - and plans to expand to the first floor.

"I don't want money. I can pay the rent," he says. "I need help with punching bags. We have an opportunity with the space." That day, the ground floor was a bit flooded by a thunderstorm the night before.

In boxing, success is about anticipating the opponent's next move. It's like dancing and playing chess - simultaneously. And once boxing is learned, street fighting is discouraged. The idea is to use intimidation before any fight even begins.

Collette, a gymnastics instructor on weekdays and South Street waitress on weekends, didn't shrink away from road rage when a car full of angry women followed her home.

"My son was with me," Collette recalled, "and this woman pulled into my driveway with four of her friends. She came over and poked me in the head and –."

One poke in return, the women knew what they were up against. End of altercation.

Some fledging boxers arrive fueled by ambition. "I want to make millions," says 13-year-old Jamil Torrence, who trained at the Costello gym for a bout at the Glenolden Swim Club.

Kevin Jimenez, 20, walked five miles to the Costello gym on a hot afternoon, his options having dwindled when a Kaplan University skill-training class didn't work out.  But life changed with the birth of his daughter, Alani. "It was the most real moment of my life," he said. And though he loves sports, he's too short for serious basketball.

When the Costello doors open, boxers scramble up three flights as a prelude to their cardio workout. Jimenez follows, wraps his hands in white cloth - the first step - and gets to work.