What does this have to do with skiing? The answer is that Rodnunsky adapted his Cablecam technique for an ambitious ski- and snowboard-tuition machine, which has recently arrived in the United Kingdom.
Rodnunsky's Metroski simulator combines a skiing surface, on a platform whose pitch is controlled by hydraulic rams, with a video system which shows footage of a "ski-instructor". Rodnunsky erected cable runs at the resort of Vail in Colorado, and a camera attached to them was used to film skiers - from behind - as they went down the piste. These sequences, shown on a screen in front of the platform, allow pupils to follow the skier and imitate his technique just as they would a ski-instructor on the slopes.
The simulator will be formally launched in the UK at next week's European Fitness Convention at Earls Court. But during the first two months of this year it was installed at the Chiswick Riverside health and sports club; while it was there I took the opportunity to ski down the slopes of Vail.
Beginners start on the smaller of two platforms, a sort of nursery slope which pitches forward to create the angle of "descent"; having mastered the skills involved, pupils move on to the red run, a bigger platform which can also pitch laterally. Before climbing up on to the beginners' platform I put on boots and skis and was strapped into a harness: this attaches to a cable hung above the Metroski and, in the event of a fall, the tug on the cable automatically stops the machine and returns the platform to a level position.
The platforms are covered with carpet: it is fine, silky stuff but since it has far more grip than snow, the skis have a special coating to help them glide over it. At the centre the carpet is a continuous roll; and when my instructor - Peter Walker, marketing director of Metroski UK and a former member of the British ski-racing team - switched on the machine, the platform slowly pitched forward and the carpet began to roll up the slope.
Skiing in the same spot while the earth moves for you is not a natural sensation. But cajoled by Mr Walker, I began to experiment with a snowplough position, until I found one which kept me sliding downwards at the same speed as that of the carpet coming up. By the time Mr Walker had switched on the video, I was doing "turns" from side to side of the carpet roll, beginning to appreciate the virtues of the Metroski.
Like other artificial surfaces, the carpet is less forgiving than snow but responds well to good technique. Mr Walker set about perfecting mine: to stress the need to keep my upper body facing down the slope while my skis moved diagonally in front of me, he advised that in the correct position "you don't crap on your skis". Perhaps it was a metaphor; or perhaps I just looked more alarmed than I was. The big platform increased my anxiety, particularly when Mr Walker selected a dramatic downhill sequence, and set the carpet roll to "fast". I couldn't keep up with the on-screen instructor - a problem with the big platform, since its lateral pitching is co-ordinated with the instructor's turns.
At the time, the lateral pitching seemed quite natural; later it occurred to me that while the forward pitch did simulate a ski slope, there were no real-resort conditions which the lateral pitch replicated. Mr Walker explained that "the skis don't bite into this surface as sharp edges will in snow, so the surface has to be tipped from side to side".
The technology to do that - and the Metroski's other tricks - costs a lot of money: Metroski UK is selling the simulators in Europe for pounds 75,000. A lesson on the Metroski doesn't come cheap either, at pounds 34.99 for an hour. Is it worth it? If the alternative is a dry ski slope, the answer is yes.
If you want to try it, there will be a Metroski at the Riverside Club in Northwood, Middlesex, from 6 March. And I can at least guarantee that you will find it more fun than sitting through True Lies.
The Riverside Club, Northwood (01923 848000): the Metroski is available for use by non-members. Metroski UK (0171-323 0240)
Ski holiday advice, page 3