Young @ Heart is another digital documentary, though by now it would be more noteworthy if a documentary were not digital. This one, leaning on the usual crutches of interviews and narration, centers on a Massachusetts touring chorus of very senior citizens who perform a repertoire of punk and rock: the Ramones, the Clash, the Bee Gees, Talking Heads, Sonic Youth, James Brown, that ilk. It looks like fun for them, and a fair amount of that fun trickles down to the audience. British director Stephen Walker, also the narrator, follows them through a seven-week rehearsal period for a new tour, and along the way he picks up bits of geriatric good humor (“We went from continent to continent till I became incontinent”) and interjects several full-blown music videos made by the film’s producer, Sally George. It isn’t all fun, however. Two of the members die within a week of each other, and the tribute songs to them, Dylan’s “Forever Young” and Coldplay’s “Fix You,” the first sung to a captive audience of prison inmates and the second on opening night of the tour, demonstrate convincingly that the act is more than just a gag.