It’s a weekday afternoon at the Flight Deck in Oakland, and Lindsay Krumbein is putting her Gritty City Repertory Youth Theatre performers through their paces. Actors Dashawn Franklin, 19, and Aly Burton, 21, rehearse a complicated scene in which their characters, in different cities, are texting each other and talking to themselves. Whenever one of them pauses to listen as if conversing in person, Krumbein has them do it again, prodding them to pick up the pace.

“Playfight” is Gritty City Rep’s first play set in Oakland, and it’s the first original play written and directed by Krumbein. The group performed an original work once before, “Caught Up” in 2013, a theatrical collage assembled from existing fragments on the theme of mass incarceration.

Krumbein hadn’t originally planned to write “Playfight” at all. “I had this idea for this play and I tried to commission it,” she says. “One of the people I talked to was Amy Sass of Ragged Wing Ensemble. She looked at me and said, ‘I think this is your play. I think you want to write this play.’ I was like, ‘No! I don’t want to write a play.’ She was very wonderful and encouraging, and I decided I would just write a really bad play and then no one would ever have to know about it. And then it wasn’t so bad actually. It was funny and it worked, and I liked it a lot better than I thought I would.”

It’s about Lucio, a bright and cheerful 19-year-old who’s effectively homeless, with one parent on the street and the other in Brazil. He lives in the West Oakland gym where he’s a student of capoeira, the Afro-Brazilian martial art. It’s 2012, and the characters get caught up in events leading up to the Black Lives Matter movement.

“Much of how the gym operates is really how our ensemble operates,” Krumbein says. “It’s a support system, and the development of pride through rigor and physical exertion and the way you become close to people that you sweat with. I tend to get really close with a lot of the kids I work with. It’s not like this character is this kid and this one is that kid, but certainly the stories that the characters are experiencing are based around many, many conversations with many, many teenagers over the years.”

That strong sense of investment in her students’ development is what led Krumbein to found Gritty City Rep in 2012.

“I was a public school teacher for 11 years, and I did after-school theater production programs,” she says. “So when I opened Gritty City it sort of evolved from the way I did programming at high schools.”

Participants generally range from ages 14 to 22 and commit for a year, performing a contemporary play in the fall and Shakespeare in the spring. Many of the performers have been with Gritty City for years, some of them since the company’s first show. Others include some of Krumbein’s former high school students.

The company’s mission is “providing a platform for young artists of color to train in theater,” she says. “And it’s a hundred percent free. We go and actively recruit at schools that don’t have theater programs, places where a lot of times kids aren’t accessing opportunities because they’re struggling. A lot of our long-term members hadn’t even seen a play before they started training with us.”

“So much of this is relationships,” Krumbein adds. “Once you’re in, you’re in the family. It’s also very, very rigorous. You better know your lines, and you better not be late. But I think kids are hungry for that. I think where they really thrive is that I’m like, over my dead body will you not be fabulous. I’ll get you there, but do your part. There’s deep trust that gets built.”

Contact Sam Hurwitt at shurwitt@gmail.com, and follow him at Twitter.com/shurwitt.

‘PLAYFIGHT’

By Lindsay Krumbein, presented by Gritty City Repertory Youth Theatre

Through: Dec. 17

Where: The Flight Deck, 1540 Broadway, Oakland

Running time: Two hours, one intermission

Tickets: $5-$50; 510-575-9427, www.grittycityrep.org