There must be something about the calisthenics of jazz drumming that generates high-performance longevity. Jimmy Cobb, who kept the time on Miles Davis' seminal album "Kind of Blue," is still going strong at 85. And Roy Haynes will probably celebrate his 90th birthday next year by gigging with his band.

By those standards, Billy Hart is a mere young'un at 73. It only seems like he's been around forever.

After more than 50 years of providing invaluable support to dozens of artists on hundreds of recordings — including extended stints with Jimmy Smith, Herbie Hancock, McCoy Tyner and Stan Getz — the irony is that Hart has never enjoyed a higher profile than he does today.

"Yeah, at a time in life when most people's situations are mellowing, mine is intensifying," Hart says, and you can almost hear his wry smile over the phone.

His recent good fortune stems from the success of the Billy Hart Quartet, which has released two acclaimed albums on the ECM label in the past three years and is currently engaged in a world tour that stops next Sunday at the Dakota Jazz Club in Minneapolis.

The quartet is distinguished by a subtly unique approach to the classic interplay of bebop. The music is quietly forceful yet shorn of bombast, with a sense of open-ended, and open-minded, possibility that's grounded in trust, self-assurance and tradition.

Mark Turner, Ben Street, Billy Hart, Ethan Iverson

These virtues are rooted in the cross-generational respect and generosity of spirit that exists between Hart and his three forty-something cohorts.

"Everything Billy plays is authentic," says quartet pianist Ethan Iverson, best known as a member of the Minnesota-rooted post-modern jazz trio the Bad Plus. "By authentic, I mean that while Billy has his own way of playing, he also comes out of something distinctive.

"He is an Afro-American born in the '40s in Washington, D.C., at a time when there was no formal education in jazz — it came out of the clubs and the streets. There was no perspective other than being in it, and when Billy was good enough at it, Jimmy Smith came along and hired him."

To Iverson and his bandmates, tenor saxophonist Mark Turner and bassist Ben Street, "Billy is the jazz tradition. But he doesn't look back to the past. He supports innovation and always wants to bring something new to the table."

Learning through teaching

Hart credits his immersion into teaching about 20 years ago with fostering that attitude.

"It brought me in contact with a new energy and made me aware of younger generations of musicians. I began to spend more time with them than with my peers. Well, some of them aren't that much younger, in their 40s and 50s. But they were looking for a connection to tradition that would bring depth to their creative spirit."

Hart and Iverson met at a rehearsal held by obscure German trombonist Christophe Schweizer and immediately hit it off. Hart recalls that Iverson "began introducing me to some other younger musicians." In 1999, the Ethan Iverson Trio released "The Minor Passions," with Hart and future Bad Plus bassist Reid Anderson.

Four years later, the Ethan Iverson/Mark Turner Quartet laid down tracks for a week in New York with Hart and Ben Street as the rhythm section. The sessions went so well that Hart asked the group if they could be the band for his gig in his new hometown of Montclair, N.J.

"Things were immediately much better and more powerful with Billy on the mike and us mostly playing Billy's tunes. The three of us just looked at each other and agreed that we should be Billy's band," Iverson says.

More than a decade later, the Billy Hart Quartet has increasingly found more time to strengthen its bi-generational affinity.

"Yard," the lone brand-new Hart original on the latest disc, "One Is the Other," has a whiff of the funk that Hart laid down in the organ-jazz setting with Jimmy Smith so long ago, but it is clearly a contemporary composition. Ben Street's song "Lennie's Groove," dedicated to iconoclastic '50s composer Lennie Tristano, is on the disc because Hart embraced it after hearing it from one of his students.

"When I first came on the scene, bands worked together 30 weeks out of the year. We're finally getting to spend some time together," Hart said from a hotel in Norway, where the group had just landed as the latest stop on their tour.

"We're exchanging ideas at a high level and bringing out the best in each other. I think we have enough music for one or maybe two CDs, but we just put out a CD last month, so we'll have to wait."

He paused for a moment. "It's Scandinavia in the summer. Things couldn't be more beautiful."