The 32-year-old singer, who is also a judge on NBC's The Voice, owes that body to a mix-and-match yoga regimen he practices at home, at the recording studio, and on the road. "At any Maroon 5 concert, you'll see a room backstage marked yoga," he says.
Living the plugged-in celebrity life in Los Angeles, Levine was aware of the yoga scene but initially kept his distance, turned off by what he calls "the cheesy clichés." But he began to worry that his gym routine was a dead end, hurting more than it helped: "Weights made my neck thick, and I would be like, 'I'm turning into a monster!'" As he grew increasingly frustrated by lower-back pain and tight hips and hamstrings, he decided to give yoga a try. That was five years ago, and Levine hasn't lifted a weight or entered a gym since. "Yoga takes what you have and molds and sculpts it, which is a much more natural way to look and feel," he says.
Credit Levine with a refreshing candor about the aesthetic payoff: "I don't like how people bullshit about how yoga is not about vanity." Not that he doesn't appreciate the spiritual benefits—Levine sees his routines as a therapeutic antidote to the distortions of his career. "Playing a show before thousands of people is a highly unnatural state," he says, "and when I get on the mat to do an hour of yoga before the show, I come out physically relaxed."
The man behind Levine's transformation is veteran New York City yoga instructor Chad Dennis. At a friend's suggestion, Levine met him for a session, and within months Dennis was traveling with Maroon 5. On tour, he puts Levine through daily routines that draw from a variety of yoga schools. Sometimes the poses are slow and repetitive: "For me, that's a form of meditation," Levine says. Other times they are muscle-quiveringly difficult: "He'll take me on a friggin' obstacle course of yoga." All of it, he says, adds up to "an investment in happiness for the rest of my life."
Adam Levine's three essential poses:

1. Headstand I: Levine is a fan of this Sirsasana pose because it generates a good sweat and takes an intense amount of concentration to avoid falling over.
2. Half-moon with hands in prayer: Levine has worked on this pose to open up his chronically tight hips.
3. One-Legged Koundinyasana II: All the weight is supported by the arms, so it's a great way to strengthen your chest and shoulders.

The five styles Levine swears by:
Levine's yogi, Chad Dennis, mixes up yoga styles to keep the singer perpetually challenged. Here are the stylistic ingredients in Levine's home brew:
Ashtanga: The basis of Levine's routine, this relatively high-speed style relies on a set sequence of poses and emphasizes continuous movements in between. May be too much for the beginner.
Vinyasa: A less intense version of Ashtanga, this focuses on synchronizing the breath with the movements that connect the poses.
Jivamukti: Combines a movement with music and Hindu spirituality. Levine steers clear of the dogma but is into the music and the physical flow.
Iyengar: A slow-moving style that is based on poses precisely held, often for extended periods of time. Dennis has created his own higher-energy version.
Anusara: This melds Iyengar's clinical sensibility with a Hindu-derived spirituality. Levine does lots of Anusara-influenced chest-opening postures.