“Good athletes,” David Foster Wallace writes in his essay “How Tracy Austin Broke My Heart,” “usually turn out to be stunningly inarticulate about just those qualities and experiences that constitute their fascination.” Wallace was referring to his disappointment with the ghostwritten memoirs of a tennis pro, but a new documentary about the legacy of a once-famous boxer bears out his assertion. In The Good Son: The Ray Mancini Story—a kind of second-rate TV movie for sports fanatics, replete with chintzy aesthetics and a score better suited to melodrama —Mancini himself dictates his personal history as if he were regaling company over dinner, meandering through long-winded anecdotes as though his every formative experience were inherently fascinating. The truth, of course, is that Mancini has long since faded from popular imagination, and so, too, has vanished the infamy of his final bout, when Korean boxer Kim Duk-Koo was killed by a blow to the head. Director Jesse James Miller locates this accident as the dramatic heart of the picture, but his attempts to draw catharsis from tragedy reek of exploitation: The final scene finds Mancini sharing a tender moment of reconciliation with Kim’s son and widow, a gesture the film stages with such maudlin embellishment that it feels like the climax of a daytime soap. All this makes for an aggrandizing bit of sports portraiture. Mancini, who served as an executive producer, is glorified and exonerated, yet it’s his inability to render either process interesting that ultimately sinks the picture.