Underman, The Roundhouse, London

The tears of a clown bring the audience down

Men support each other in the largely dull Underman (Laurie Lewis)

The clown with a broken heart was already an overworked trope when Marcel Carné made the film Les Enfants du Paradis in 1939. A lovelorn acrobat in 2012, then, is hardly going to wring any more juice from the image, but three lovelorn acrobats who happen to be chunky, beardy Vikings ... that starts to be interesting again.

Underman is the Swedish term for the chap at base camp in an acrobatic pair, the steady, unglamorous one who supports and catches the flyer, who is usually a woman. Because of the intimacy and trust involved, it's common for working pairs to be lovers. But what happens to the underman when the flyer flies away?

Bookended by the comically pathetic image of a lone traveller carrying human hand luggage, Cirkus Cirkor's show Underman, part of CircusFest 2012, is about three newly single men's efforts to redefine their maleness, battle a fear of heights, and find new outlets for energy temporarily diverted into facial hair.

One tells the story of his first date, then climbs inside a giant bicycle tyre to spin his memories into oblivion. Another performs an acrobatic duet alone, supporting and catching ghostly nothingness with tender precision. A third swings kettlebells – a bit of a mis-step: these iron lumps may be capable of crushing a man's skull, but their handling on stage is unengaging.

Some of the material travels way off-piste. Peter Aberg, the giant of the trio, while balancing a feather on a stick balanced on his chin, demonstrates final-stage tactics in completing Rubik's Cube. (He spent four years working at this, he reveals. You wonder if that's why his girlfriend left him.)

Andreas Tengblad, who wrote the music and plays guitar in the acrobats' band, sings a drippy ballad on his knees while accompanying himself on the cello. Later he brings out a ukulele and smashes it to bits when it won't play in tune. Less petulantly, jugglers lob random batons to the drummer, who lobs them back without missing a beat. Love it or loathe it, there's a slightly sticky emphasis on damaged egos opening up to group therapy.

But touching as it is to see Iron John types cradling each other like babies, the material is too slight to fill 75 minutes. And asking an audience to change seats halfway through ("you never know who you might meet!") only confirms the lack of tension. If there's one thing sadder than a broken-hearted circus artiste, it's dull circus.

CircusFest 2012 continues to 29 April (0844 482 8008)