Proves once and for all that documentary heavyweight Frederick Wiseman's mesmerizing fly-on-the-wall filmmaking style -- in addition to being endlessly compelling -- is also infinitely adaptable.

The soundscape, too, is endlessly fascinating, a layer cake of squeaks, grunts, gasps, and rattling chains that, combined, catches a rhythm that sounds an awful lot like song.

Wiseman records the rituals of repetition (speed bag and footwork) in poetic long shots that often have two pugilists side by side, each unaware of the other. The cadence is both primal and hypnotic.