There was an audible thud when Ari Loeb fell on his backside in the midst of a scrappy, eight-against-one brawl at the Signature Theater Company recently. The fight was fictional, of course: Mr. Loeb was rehearsing the finale of “Kung Fu,” the new play by David Henry Hwang about the martial arts master Bruce Lee that is now in previews at Signature, where it opens on Monday.

The choreographer Sonya Tayeh asked Mr. Loeb, one of Lee’s adversaries, if he was O.K. “I think so,” he replied. (He was.) The next few minutes were spent finding a better way for him to fall — or to be thrown, really — and the short episode highlighted the complexities of making stage fighting look real to an audience while remaining safe for the performers. The process, which that day included several other tweaks to address the twin concerns of safety and verisimilitude, is grueling. It can take hours of rehearsal to create just a few minutes of fast-paced stage time.

“Kung Fu,” which traces Lee’s life from the age of 18 until a few years before his death at 32, draws on the skills of Cole Horibe in the lead role. He is most recognizable to audiences from the television competition show “So You Think You Can Dance”; he was a contestant in Season 9 of the series, and became known for his “martial arts fusion” style.

Mr. Horibe, 28, who was born and raised in Hawaii, began studying martial arts when he was very young. While the movement in the show is very quick and looks quite realistic, it’s a significant adjustment for a guy who was trained actually to hit, not to pretend.