TORONTO — In 45 minutes, Ramin Karimloo would take the stage as Jean Valjean, the antihero of the decades-spanning musical “Les Misérables.” But for now, he was doing chin-ups off the edge of a balcony on the set, his tattooed arms in full Popeye flex. To warm up his voice, he did scales, all the while fending off attackers as he worked out the kinks in a fight scene. He never stopped moving, lightly bounding around the Princess of Wales Theater stage here as if his motorcycle boots were spring-loaded.

In Victor Hugo’s epic 1862 novel, the source for the musical, Valjean is imprisoned for 19 years after stealing a loaf of bread to feed his ailing sister. The escaped convict’s quest for a life of grace is thwarted by the relentless pursuit of a police inspector, Javert, and buoyed by the love of his adopted daughter, Cosette.

Mr. Karimloo, whose effusiveness makes him seem younger than 35, decided early on that his Valjean would never lose his physical edge, which meant five months of training and a lot of protein powder. In his dressing room post-warm-up, while a makeup artist smudged prisoner’s soot over his face, he said his young Valjean has hints of Ultimate Fighting Championship brawler Randy Couture, and his older Valjean was in part inspired by watching Al Pacino walk commandingly through an airport, parting the crowds.

“Valjean’s body says a lot about his mentality,” he said. “In prison, Valjean educated himself. His brain became his sword, but he came out ready to fight.”