It's not every show that puts its audience to work. But then, as the voice booming over the speaker system says, we "are part of the machine." Collectif and then…'s interactive circus installation turns the theatre into a factory floor. We become its production line - a demonstration of the labour-leisure system that binds us all. The Machine might have won the Oxford Samuel Beckett Theatre Trust award, but it's safe to say the Nobel won't be following.

Handed lab coats and safety goggles, we worker-watchers are anonymised. The name badges on our chest read either ‘John' or ‘Mark'. Signing in, we're attributed meaningless, repetitive tasks – one role in the whole. I'm to tie plastic bags full of a co-worker's breath. Others pedal conveyor belts into life, pour water down spouts or collect sand in sacks. We're cogs in a vast Rube Goldberg machine. When the voice says jump, for no apparent reason, we all jump.

Between shifts, we get spectacle. As reward for our work, the managers put on a show. Showered in silver glitter, they sparkle through circus routines. It's a mark of the way leisure is entwined with work - not distinct from it, but a central motivating factor. We work to play - then get back to work.

Circus makes a smart parallel, because it shows bodies at work. In showing the strength and stamina involved, Collectif and then… make clear the labour behind leisure; that entertainment is employment in itself. However, their work contrasts with ours - not just because it's more individual, skilled rather than soul-destroying, but because it uses the whole body, not just a part.

Each act pushes the performer to some kind of limit; testing bodies or wearing them down. Handbalancer Natalie Reckert's legs are loaded up with bags of water, until she inevitably tips. Aerialist Lucie N'Duhirahe holds all the hot air bags she can handle. Yet, it's only Hyde's hair-hanging that really feels dangerous.

She's pulled up by the roots, attached to a pulley system that's weighed down by our sandbags. As she describes the agonising pain of it, how she's pushed herself from one minute to four, it's up to us how long she – our manager – hangs there. To help her, we have to rebel against The Machine.

Frankly, though the circus isn't up to scratch; neither enough skill, nor enough variety. A ropes routine, gliding along a girder, is ungainly and the apparatus itself gets in the way. Francesca Hyde turns a conveyor belt into a travelator, only with little impact or expression, and while Reckert's handbalancing has its moments – her legs wind and unwind like a sprung coil – it's nowhere near spectacular enough to carry a show. It all feels stretched thin: run of the mill circus with a lot of packaging.

Collectif and then... - The Machine runs at the Barbican until 8th October.