Ian Anderson has been celebrating the 50th anniversary of Jethro Tull on stage for about a year now; so, technically, he’s celebrating 51 years of Tull.

But that year, musically, appears to have been well-spent in sharpening up his band’s chops.

Last year, Anderson brought the party to the Toyota Oakdale in Wallingford. On Sunday, Sept. 15, the Mohegan Sun Arena hosted Ian and the boys.

The group sounded great a year ago as it ran through the catalogue of Anderson’s old group.

But at the Mohegan, Anderson and crew – guitarist Floridan Opahle, drummer Scott Hammond, keyboardist John O’Hara, and bassist David Goodier ‑ sounded even better.

(Although Jethro Tull’s name is printed large and Anderson’s name is printed in fine print, this tour really is Anderson celebrating Tull, not the band Jethro Tull itself.)

The sound of Anderson’s group was more muscular, somehow, in 2019. It crunched and roared like the best arena rock of old. And they seemed much tighter after a year or so on the road.

Anderson’s voice also seemed stronger than a year ago. It’s more reflective of the Anderson of old, even if the highest notes were still out of reach. (Anderson still hands over the high notes to his bandmates and, on a few occasions, some videos projected behind the band. The videos took over “Heavy Horses” and the old war horse, “Aqualung.”)

Ian Anderson performed the music of his old band Jethro Tull in a concert at the Mohegan Sun Arena on Sept. 8. MICHAEL CHAIKEN REPUBLICAN-AMERICAN

And Anderson, well into his 70s, also proved to be as spry as ever. Some of his musical generation will take long breaks back stage to catch their breath. But Anderson would only walk over to stage right to take a swig of water before rejoining his band under the spotlight. And Anderson still managed to pull off his trademark flute solos played on a single leg. He also still dodged and dipped as he sang as if it were 1972 all over again.

Although Tull’s catalogue is deep and long-ranging, the set list at the Mohegan Sun was heavy on the classic rock favorites. The group trotted out favorites such as “Aqualung,” “Thick as a Brick, “Locomotive Breath” and “Too Old to Rock and Roll, Too Young to Die.”

This best-of-album approach is to be expected for an arena show with a near sell-out crowd. Anderson has said that for many classic rock fans, the group sits squarely in the same popular light as Led Zeppelin, Deep Purple and Black Sabbath.

Most of the set on Sept. 8 drew from albums prior to 1978’s “Heavy Horses.” Although, Anderson did land for a moment at 1987’s “Crest of the Knave.”

There were some deeper cuts played during Anderson’s evening at the Mohegan Sun. The group played an excerpt from 1973’s “A Passion Play” and the instrumental “Warm Sporran” from 1979’s “Stormwatch.”

For me, the highlights of the evening were the introspective “Farm on the Freeway” because it was clear from Anderson’s performance that the tale of a farmer losing his property to “progress” meant something to him. The powerful “My God” from “Aqualung” also grabbed my attention and inspired me to go back to the original album again.

The crowd at the Mohegan clearly was populated solely with diehard fans. After 50 years, the days of curious onlookers wandering into the arena to jump on the latest pop music trend is unlikely to happen. And it was clear that for everyone in Uncasville, the music of Ian Anderson and Jethro Tull still means something to them.

And Anderson and his group made sure the audience’s ardor was not misplaced.

I give Ian Anderson’s Sept. 8 performance at the Mohegan Sun Arena at 4 ½ out of 5 stars.