The past couple of decades have seen a flowering of youth, or young-professional, orchestras. The musicians of the New World Symphony, the Tanglewood Music Center Orchestra, the Gustav Mahler Youth Orchestra, the Simon Bolivar Youth Orchestra of Venezuela, many of them still students or new-minted alums, often play as well as or better than some professional ensembles: fresh, excited, in love with music, not yet jaded by the day-to-day exigencies of an orchestral career.

Yet these orchestras lack the experience or cachet of a big-name professional orchestra. This has its advantages: the audience feels it gets an insider’s peek at the talent of the future when the playing is good, but will cut the musicians a lot of slack — after all, they’re only kids — when it’s not.

The University of Maryland’s NOI Philharmonic is certainly on a par with the above-mentioned ensembles. Every summer, the 24-year-old National Orchestral Institute brings a select group of talented young musicians (aged 18 to 28) from around the country to work with a faculty drawn from some of America’s leading orchestras and three notable conductors over three intense weeks of rehearsals, workshops and performances that are an annual highlight on this region’s musical calendar. This summer, more than one person has written to let me know that I missed a treat by not having heard German composer Matthias Pintscher conduct Bee­tho­ven’s and Mahler’s First Symphonies, and his own piece “towards Osiris,” on June 18.

This year’s final concert on Saturday night was, however, a little more uneven. The ardor, of course, was there. Not only were the young players palpably full of excitement, but conductor Carlo Rizzi, former music director of the Welsh National Opera and a frequent guest at major international opera houses, brought his opera experience right into the Clarice Smith Center’s Dekelboum Hall. This made for some strikingly dramatic moments, but some rather unusual Brahms. Rizzi’s reading of that composer’s Second Symphony was colorful, sunny and Italianate — meaning that it bore the same relationship to Brahms’s architecture as a painted set flat does to a real building.

Brahms is a challenge for young musicians, but the NOI Philharmonic this year sounded particularly challenged, at least interpretively. On the one hand, the performance moved fluidly, and Rizzi had a knack for picking out small details and making them work: an adroit phrasing at the end of the second movement, or the nimble galloping at the end of a half-hysterical fourth movement.

Carlo Rizzi conducted the closing concert of the National Orchestral Institute Philharmonic at the Clarice Smith Performing Arts Center on Saturday. (Jonas Gustavsson)

But some of the important, anchoring moments of the piece, starting with the opening, were shaky. And the winds and brass had some weak moments, although they were only moments (the horn solo toward the end of the first movement was, by contrast, a dream in gold). The performance was on surest ground in the third movement, when everyone seemed to be on the same page. But overall, it either groped to find meaning (especially in the second movement) or took refuge in flashy drama.

The program’s second work was, if anything, a bigger challenge: Stravinsky’s “Rite of Spring,” commonly associated with the riots it caused at its world premiere in Paris and the dinosaur segment of Disney’s “Fantasia.” Neither association conveys much about the roiling intricacy and textures and pounding rhythms of a work written by a young and brilliant composer to accompany a ballet about pagan sacrifice.

Rizzi’s conducting didn’t necessarily convey that dark drama either; there was more of the ballet about it than the pagan. But the lightness, here, seemed an asset, certainly to the performers, who had to navigate a technically fiendish score, some for the first time. Rizzi spelled everything out with crisp gestures, helped the players out of one muddled passage and generally made the complicated, ever-changing rhythms seem clear and alive.

The result was a performance that lacked the drama or heft of a top professional orchestra but led the players, and perhaps even the listeners, into the inner workings of the piece: a tangible reminder that, even at the top level, a teaching orchestra may have slightly different goals from a professional ensemble.