Watching “Rocky Balboa” is sort of like bumping into an old acquaintance you thought had died. You’re surprised that he’s ambulatory rather than underground, but may still be distressed at his rather flabby condition. This sixth installment in Sylvester Stallone’s pugilistic series, which established the modern template for inspiring underdog sports movies in 1976 but then stumbled through four increasingly forgettable sequels before apparently expiring in 1990, will have a certain appeal for nostalgic baby-boomers, especially since its message is that you can still fulfill your dreams even as you’re approaching sixty. But any objective assessment must be that this franchise is definitely over the hill and would have been better left in the past.

As the picture opens, we find Rocky, still grieving the death of his beloved Adrian (Talia Shire, seen in a few flashbacks) from cancer, muddling by as the easygoing host at a neighborhood restaurant named after her while continuing his love-hate relationship with gruff brother-in-law Paulie (Burt Young) and struggling to maintain contact with his unhappy son Robbie (Milo Ventimiglia), who feels the pressure of standing out as his own man while living in his dad’s shadow. Rocky is discontented; even his reacquaintance with Marie (Geraldine Hughes), a local woman he’d known when she was a kid but who’s now a single mother with a son of her own named Steps (James Francis Kelly III), brightens his day only slightly.

But within his sad reverie a glimmer of hope emerges: Rocky’s like to take to the ring again. And though the state boxing commission considers the thought of a 57-year-old man putting on trunks and gloves for real imprudent (and Robbie is initially horrified), the old man’s inclination gets a push from an ESPN computer simulation suggesting that in his prime Rocky might have bested the current champ, Mason “The Line” Dixon (Antonio Tarver). Since Dixon’s getting bad press for defending his title against a string of no-talent bums, his handlers suggest that an “exhibition” bout with Balboa might just be the ticket to refurbishing his image. So it’s not long before Rocky’s training as strenuously as his arthritis will allow, and he and Mason are facing one another in Las Vegas, in a fight broadcast on HBO, with Paulie and a converted Robbie (as well as the shade of Burgess Meredith’s Mickey) in his corner and Marie looking on concernedly from the sidelines.

Don’t worry: we won’t reveal here whether Rocky gets knocked out in the first thirty seconds, wins or goes the distance (among the various possibilities). But historical experience should tell you that though he suffers, it’s not for nothing. As for Stallone’s effort to resurrect the character that effectively made his career, it isn’t for nothing, either; but “Rocky Balboa” can’t be expected to recapture the zest of the initial movie, and it certainly doesn’t. Stallone instead aims for an autumnal, almost ruminative feel, which instead comes across as poky and sentimental. As writer and director he’s much too self-indulgent, providing himself with far too many big speeches and then giving himself too much leeway in delivering them: the words, no jewels to begin with, are spoken so slowly, and are punctuated with such pregnant pauses, that one would think he deemed them of Shakespearean quality–which they definitely are not. Things get energized when Rocky steps back into the ring in the final reel, of course, but the fight montage is messily choreographed and edited, without the clarity and rhythm of those in previous episodes. And while, given Stallone’s age, it was probably necessary to pit Rocky against a less formidable-looking foe than those of previous installments, Tarver–although a professional boxer himself–looks more rap star than authentic champ.

As for the rest, Hughes is nicely natural, but Young’s shtick grows old quickly, and Ventimiglia, now a hot property from “Heroes,” can do little with a character that seems poorly conceived and badly written. And while Kelly seems a pleasant fellow, Steps’ transition from surly teen to staunch supporter isn’t made remotely credible. On the technical side, “Balboa” is closer to the gritty first movie than its slicker sequels, with Clark Mathis’ cinematography often offering images that are murky and indistinct. Bill Conti’s familiar themes return, which should be endearing to committed fans, although objectively those trumpet shouts are pretty cheesy.

One person who doesn’t show up again is Mr. T, which is too bad; Mike Tyson is hardly a good substitute, and one misses a ringside scene in which Clubber might have said of the battered Rocky, “I pity the fool.” Stallone’s new movie isn’t bad enough to necessitate that extreme an expression of sympathy for anybody who goes to see it. But though even in this incarnation Rocky remains a likable lug, he was unwise to come out of well-deserved retirement.