During a recent show in Austin, Texas, Killswitch Engage guitarist Adam Dutkiewicz busted his ass -- literally -- to give the crowd a good show.

As the band played, he jumped and screamed, then jumped some more. And since the floor was slippery, he fell. Then fell again and again and again.

"My ass still looks like a big, black swollen ham," he said with something resembling pride. "One cheek is way bigger than the other. I have a lopsided ass."

Such go-for-broke stage performances have helped earn the Massachusetts band a large, loyal following in the metal underground. And though the band's brand of music is angular, challenging and loud enough to rattle the windows even at moderate volume, Killswitch Engage are rapidly threatening to break into the mainstream.

Their latest album, The End of Heartache, debuted last week at #21 on the Billboard albums chart, and the band's current tour with In Flames is going off like a firestorm in a wood factory. But chart position and album sales are of little concern to Dutkiewicz, who has been rocking with Killswitch since the band formed in 1999.

"I never look at any of that stuff because it doesn't mean anything to me," he said. "It just means we're a number. For us it's more about getting onstage and having a good time. As long as I get my cheese tray in the back room, that's all that matters."

Dutkiewicz was joking, of course, as he usually is. If he weren't producing records (he has worked with All That Remains and Shadows Fall), writing songs and playing live, he'd do well as a stand-up comic. "I think people have gotten burned out on the rock they've been spoon-fed and they're looking for something edgier," he says of the band's increased popularity. "Maybe more people are lifting weights, so they're into harder stuff. Everybody's drinking energy drinks. Everyone wants to get it quicker, harder, faster."

Killswitch Engage spent 18 months writing The End of Heartache, and the work shows: The songs are far more lyrical than anything the group had done previously, and they're crafted with a skill that makes them seem like individual parts of a complete puzzle, yet without resembling prog-rock.

"We really just wanted to make a collection of girl-rock songs," Dutkiewicz quipped. "We want to appeal to women and make love-metal." He chuckles, then shifts into reality mode, as he usually does following a sarcastic answer. "Honestly, we just wanted to write music we were stoked about. This is just the next record of our career. It's like 'Star Wars Episode III,' only we did our episodes in the right order."

When pressed to analyze how The End of Heartache differs musically from 2002's Alive or Just Breathing, Dutkiewicz again broke into wise-ass mode. "There was more fried chicken involved in the creation of this record," he said. "Seriously, it made the sound a little greasier and a little meatier."

One major difference between the new album and its predecessor is the vocals, which are capably handled by Howard Jones (ex-Blood Has Been Shed), who deftly flips from blood-freezing screams to vibrato-laden crooning. Jones joined the band in 2003 after Jesse David Leach quit the band. "His heart just wasn't into it, and he was battling a lot of problems with his throat," Dutkiewicz said. "So he ducked out."

After auditioning about 30 singers, Killswitch were approached by Jones, whose vocal range and emotive delivery matched the band's ambitions. "He fit like a snug glove," Dutkiewicz said. "He has tremendous confidence live, but the real reason we hired him is because he's big and black and he can beat people up."

Although Killswitch Engage are signed to Roadrunner Records, the bandmembers are in charge of every facet of their business, which they run like a cottage industry. Bassist Mike D'Antonio designs the artwork, Dutkiewicz produces and engineers, and the band doesn't invite anyone from the record company to hear an album until it's completed.

"I think a lot of bands should do that," Dutkiewicz said. "That way it's their voice, not the industry's voice. We do what we want, and if the record label gives us sh-- about doing what we want to do, as the producer I just tell them, 'Back off and eat a bag of d---s.

"And when you're done with that bag you can keep snacking on another one.' "