As the troupe comes to life from their seemingly relaxed, supine state, there’s a feeling of anticipation that starts to heighten as costumes are assembled. There are poles, a swimmer’s cap, heavy rocks, and a fantastically incongruous item: a suit of armour. The performers chatter and quietly cue each other as the circus staple, the lift, is repeated by duos across the stage, like so many meerkats vying for attention.

Amidst buckets and sand pouring, Backbone continues to build through feats of seemingly impossible physical extremes, but with mutability that relieves us of the predictable and somewhat manipulative “ta da” moments of a tired circus.

Jascha Boyce astounds with suit and rock, atop an equally impressive team of lifters. She has the best poker face going, but south of her head, there is not a skerrick of support. Our jaws drop. Meike Lizotte effortlessly portrays an inverse marionette, on terrifyingly high diminishing poles, until she appears to have been singularly speared. It is mind-boggling. Stand-alone stunts these are not; the entire show is this good.

The troupe tumble, somersault and fly through the air, with flagrant disregard for the laws of gravity. The imperative physical timing is impeccable, much to our relief. Director Darcy Grant’s pace is so perfectly matched to the show’s music (Shenton Gregory and Elliot Zoerner) and design (Geoff Cobham), that even within the quieter vignettes, there is audience immersion. In the frequent gasp-worthy moments we erupt with spontaneous applause. There is plenty of circuslike falling over, but without a hint of corny slapstick; the humour is to come in the form of a game we’ll call, “Fling”.

With shades of capoeira, flying drop kicks and the reverse caterpillar, the physical language is at times brutal, but never moves into the uncomfortable realm of violence; there’s far too much joy here for that. Without nets and harnesses, there’s a stage full of danger that keeps us on the edge of our seats. The seasoned performers, never doubting the sum of their parts, take us into their confidence, and by show’s close, investment in their final task is so strong, it is almost painful to watch.

There is extraordinary physicality throughout, but Backbone does not solely hang its hat on brawn; there’s as much brain in the offing. The subtleties contained within can’t be fully comprehended in one viewing; there’s simply too much going on. The sheer strength of body and character needed to round out this frenzied performance demonstrates a discipline and camaraderie, rarely seen on stage. It’s simply a joy to watch people enjoying themselves this much, because it reminds of how we used to have fun, before we became so inflexible.

Backbone provocatively shows us the freedom of strength, the best way to end an argument (hint: make your opponent fly like a plane), and the beauty of grit, sweat and muscles.

Backbone is at the Adelaide Festival Centre as part of Adelaide Festival until March 19

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