Three boxers, two men and a woman, train at a Bedford-Stuyvesant gym in this engrossing documentary, which gives equal weight to their experiences in and out of the ring. Filmmakers Nanette Burstein and Brett Morgen make good use of visual and aural metaphors to connect the different plot strands and don’t rely excessively on voice-over, but they’re almost too efficient at using documentary techniques. The material is powerful—one boxer has been accused of a crime and the trial conflicts with a crucial competition—but much of it feels predigested, the themes inadvertently one-dimensional.