Tina Turner performs at Spectrum

Tina Turner has legs, and she knows how to use them.

Turner's voice, a wild, untamed wail that has few competitors and no equivalent in the history of popular music, has always been her greatest asset, but her gams run a close second.

Her concert at the Spectrum on Saturday night, part of her first tour in eight years, offered her ample opportunity to display both.

Considering that Turner turned 69 on Wednesday, her shapely stems, accentuated by high- and low-cut costumes whose modesty has increased only slightly in recent decades, surely qualify as one of the world's great wonders.

Broken up by costume changes, a sit-down second act and a long intermission, the two-hour show was designed to give its star several opportunities to recharge her batteries, but Turner seemed hardly to need them.

During "Nutbush City Limits," the first of two encores, Turner danced her way up and down the length of a mechanical arm that swung her out and over the audience, apparently heedless of the drop below.

Turner's voice, too, has weathered the years remarkably intact. Although she left the high notes in the Who's "Acid Queen" to her backing singers, Turner scaled the summit of "River Deep, Mountain High" without breaking a sweat.

Where the show faltered was in its substance. For a performer with such singular talents, Turner has been ill-served, sometimes spectacularly so, by her material. Her four decades in the business have produced only a handful of enduring songs.

The sleazy schlock of "Private Dancer" and the kitschy overload of "We Don't Need Another Hero" were redeemed, just barely, by the force of her performance, but they served as a reminder of just how rarely Turner has matched her earth-shattering voice to songs of equal power.

While the show featured plenty of literal and figurative pyrotechnics, including eight backup dancers and a set piece inspired by Turner's role in

Mad Max Beyond Thunderdome

, its highlight was a stripped-down section drawing on her musical roots.

Opened by a gospel-inflected take on the Beatles' "Help," the seated mini-set peaked with a sultry, scorching "Undercover Agent for the Blues," followed shortly thereafter by a white-hot reading of the Rolling Stones' "Jumpin' Jack Flash."

Commercial success has taken her into slicker pastures, but Turner is still at her best when she's ankle-deep in Tennessee earth, when she takes it, as she once said, nice and rough.