I was using a fitness ball (swiss ball, exercise ball, gym ball, etc) to sit on in the study in lieu of a normal chair.  I have to be honest and say that the experiment wasn’t working for me (it was supposed to get me disciplined to keep straight posture while seated) and I was considering giving up and going back to a chair.  The decision was made for me yesterday when it burst while I was sitting on it.

I’ll admit, it was helped (but not deliberately).  I had bits of PC case lying all over the floor, and I was rolling around to reach something to one side of me[1]…  The ball pushed onto the corner of a CD-ROM drive bracket, hard enough to pierce the rubber.

Before I talk about what inevitably happened next, I need to mention that the manufacturer of the ball labelled it “anti-burst”.  I actually gave this a bit of thought — not to the point of buying an anti-burst type over one that made no such claim, but more that I was intrigued by the thought of what a large rubber sphere filled with air to a sufficient pressure to keep 100+kg of human off the floor was supposed to do when breached if not burst.

Also, just prior to my deciding to start using a gym ball as an office chair I had listened to This Week In Tech Episode 98, “The Big Bang”, in which the show’s host famously, during the episode, experienced a “catastrophic decompression” of his own swiss ball.  In fact, ironically, that event was my inspiration or motivation to use a gym ball (and if you can figure that out for me, I’d appreciate it).

If you listen to that episode (as one poster to the TWiT forums said, “the magic happens at 47:30″) you hear quite a loud explosion as Leo’s ball gives way, followed by impacts of various objects (including Leo himself).  He described it as “my swiss ball exploded”.

My experience was nothing like that!  As I said I was sitting on the ball and rolled toward what I was working on.  I heard the sound of the ball being pierced, and a slight hiss of air — but I was still sitting.  I realised instantly what had happened, but before I could actually move the ball gave way and dropped me to the floor.  About a third to a half a second elapsed between the sound of the puncture and my assumption of a new lower seating position.

Picking myself up, I inspected the carcass of the ball and found a single tear in the rubber that was nearly half the ball’s circumference — the initial hole travelled as the pressurised air was forced through.

So was the ball “anti-burst”?  I’d have to say yes.  It still failed, but not in the way that Leo’s ball went BANG.  There was virtually no sound (other than me hitting the deck of course) and even though I didn’t have enough time to jump off the ball or otherwise avoid the fall, that might just be because I’m on the heavier end of the scale.  Someone lighter may well have put the hole under less stress and caused it to rip later or slower (or maybe not at all).

So if you’re a gym-equipment-for-office-furniture type of person, having lived through the event I’d say definitely get the “anti-burst”.  Sure, it won’t keep you off the floor if it gives way, but it’ll be a smoother ride down.  You’ve probably got more to worry about from possibly hitting your head on the desk as you go down (I reckon I was perilously close to that this time, as I had my back to the desk), or from landing on the tacks your “friends” put out to find out if your gym ball is the anti-burst kind.

Oh and I’m fine, by the way…  ;)

[1] Anyone who’s used one of these things as fitness equipment or as office furniture will understand the movements you just pick up like second-nature.  Office-chair users: when you need to talk to your buddy at the next desk, you don’t think twice about turning around and pushing yourself backwards across the floor to reach her do you?  Same kind of thing.