MUSCLE, Pegasus Players. Composer William Finn and playwright James Lapine, coauthors of Falsettos and A New Brain, teamed up with lyricist Ellen Fitzhugh for this musical about a guy who gets a new body. Set in mid-80s New York, the show concerns skinny, insecure Max, a manuscript reader at a publishing firm who’s inspired by a biography of Arnold Schwarzenegger to transform himself from an awkward academic into an iron-pumping, steroid-shooting superman. His obsessive self-reinvention alarms and alienates his friends and family, whose company he rejects in favor of guys with names like Ajax and Jocko. Yet Max’s journey “down the rabbit hole” of California’s competitive body-building subculture makes him realize that he can’t escape his emotional weaknesses simply by building up his physical strength.

Finn’s propulsive rhythms and fertile melodic sense make Muscle worth listening to, and Fitzhugh’s words have a nice deadpan humor, though they’re markedly inferior to Finn’s own Falsettos lyrics. But Lapine’s script, populated by generic caricatures rather than complex characters, lacks the psychological specificity needed to make Max’s odd odyssey comprehensible or meaningful–the show starts out strong but loses its way. Director Gareth Hendee’s world-premiere production is solidly staged and acted, with particularly good work coming from beefy, bald Timothy Jon as Max’s mentor. The real star of the evening is musical director and pianist Jon Steinhagen, who skillfully guides the ensemble through Finn’s driving, complex score.

–Albert Williams