If you want to see what really early break dancing looked like -- we're talking prehistoric -- check out the moment in Wattstax when Rufus Thomas, the rambunctious jester of Memphis soul, performs a cocky little number called ''The Breakdown'' and a handful of kids in the audience begin to bend, flop, and shake their limbs as if electric currents were zapping through them. The dance is pure play (a few of these impromptu groove artists wear hats twice as big as their heads), yet it's clear now, in a way that it wasn't then, that the daffy street movements would soon begin to fuse into something far grander: the cultural revolution of hip-hop.
This particular scene unfolded on the sunny afternoon of Aug. 20, 1972, during a seven-hour concert held at the Los Angeles Coliseum to commemorate the Watts riots of 1965. The music was soul, blues, and a stray bit of futuristic funk; the acts included Albert King, the Staples Singers, and Isaac Hayes, and barely a white face could be seen in the stands. At the time, the notion of 110,000 African Americans turning out for their own Woodstock seemed nothing less than a triumph of solidarity. Yet if you go to see ''Wattstax,'' the 1973 film of the event that is being rereleased for the first time in 30 years (it has never been available on video or DVD), it may strike you that what once looked like an exultant expression of black unity now carries, in hindsight, an eerie aura of segregation. Any 1970s nostalgia is tempered by a grateful awareness that we are now, in many ways, less divided.
I wish I could say that ''Wattstax'' was an ecstatic soul celebration, but most of the performances, while enjoyable, fall short of memorable. Two of the best aren't even from the Coliseum concert: The Emotions do a delirious spiritual at a local church, and Johnnie Taylor, singing ''Jody,'' makes the sweat drip at a packed nightclub. On stage in the middle of the Coliseum football field, most of the other performers, such as Little Milton and Luther Ingram, burn less brightly, though Rufus Thomas has a tremendous bit in which he waves the audience out onto the field to dance to ''Do the Funky Chicken.'' The new ''special edition'' also includes a climactic appearance by Isaac Hayes, which was cut entirely from the original film due to a dispute over music rights. His performance of ''Shaft'' is far less dramatic than his signature outfit: bare chest bedecked with gold chains -- I mean real chains -- that make him look like Mandingo dressed by Karl Lagerfeld.
''Wattstax,'' like ''Woodstock'' before it, presents a music festival as a larger political statement. Jesse Jackson, in full 'fro, introduces the concert by exhorting the crowd to shout ''I...am...somebody,'' and the director, Mel Stuart, cuts from performance sequences to encounter-group dialogues with Watts residents to clips of Richard Pryor improvising at a local bar, the ferocity of his wit bubbling up from the rage of his persecution. Yet it must be said that the movie, arriving as it did on the cusp between civil rights optimism and the street fire of blaxploitation, now plays with a strangely desultory air. Three decades ago in America, a stadium concert that featured musicians of universal passion could still bill itself, proudly, as separate but equal. To see ''Wattstax'' today is to realize why that moment had to end.