Directed by Sue Bourne. PG cert, gen release, 97 min.

ONE MEASURE of a successful documentary is its ability to interest viewers in a subject to which they had never paid much attention. A few years ago, Spellboundmanaged that feat with its study of the spelling-bee phenomenon. If you've never given Irish dancing a second thought, there is no reason to fear Jig. Sue Bourne's beautifully balanced film should win over even those terminally resistant to this peculiar art.

Jigconcerns itself with entrants to the 2010 World Irish Dancing Championships in Glasgow. We are unsurprised to encounter young female competitors from Dublin and Derry. The brain does not judder upon meeting equally eager hoofers from the US and Scotland. Bourne is, however, intent on stretching the net as wide as possible.

In the course of a busy opening half, her film – presented without voice-over – finds space for a keen Dutch fellow (who speaks the best English heard in the film) and a group of girls from Moscow (who are upbraided for looking too darn miserable).

Initially, fears abound that there may just be too many faces on display. But as we advance towards the big championship, Jig's focus closes in on the competitors that matter. The closing third is as exciting as any sports documentary.

Visiting Hibernophobes in search of snark and satire will leave disappointed. The outrageous wigs and heavy make-up worn by the young girls do send up a few reminders of those ghastly juvenile beauty pageants, but no hint of undue sexualisation hangs around the exhausting performances. The parents are wearyingly dedicated, but rarely seem aggressive or pushy.

If Jighas a flaw, it is its reluctance to explain precisely why one dancer is better than another. (Watching Spellbound, one understood why any competitor who inserted a "j" in "estrogen" would be expelled.) Mind you, that pair who actually crashed into one another can't have been doing the right thing. Can they?