Surf the turf, to play chicken on a mountain

It looks a bit like a skateboard, but with three wheels instead of four, and off-road tyres. It does have a brake, but that doesn't work in the wet. Eric Kendall goes mountainboarding.

With the rain sheeting down we headed hillwards, trailing our "mountainboards", unsure what to expect. To judge from the knee- and elbow-pads and helmets, it seemed likely that we'd have a few tumbles.

These "outback", or off-road, mountainboards are apparently ideal for snowboarders without snow, or for surfers when the weather's too cold for the beach. They obviously have something in common with skateboards, but my limited memory of those things was that bumps were a problem. A falling-off kind of a problem.

However, mountainboards have been specifically designed for rough terrain, with big, chunky tyres, optional toe-straps and a low-slung board that hangs between the wheels rather than perching on top of them. Beyond that, nothing remarkable, apart from the three wheels. That makes sense when you see one roll into a turn, the front pair of wheels steering, the rear one trailing and the brake not working.

The board is not too good in mud, and frankly, it wouldn't bring you to a white-knuckle halt even in a desert. In any case, the chances of operating it with your foot, in extremis, are slim. When things get bad it's better to concentrate on trying to turn out of the fall line (the steepest route down). The alternative is to bail out cleanly - leaping clear and getting your legs going before hitting the ground, to minimise the chances of a body-slam into the hillside. Rail commuters would be naturals - the run-off technique is learnt the same way as when alighting at speed from a carriage: you do it facing the wrong way only once.

First impressions, that riding a mountainboard is impossible, soon give way to the conviction that you've been given a duff board. The slightest weight adjustment tilts it to one side, which feels alarmingly unstable but is in fact all part of the plan: you steer by tilting. Flip the board over, and all is revealed - a steering linkage that turns the front wheels, depending on which way and how heavily you weight the board.

The first tentative rides, barely moving at all, feel like learning to juggle: either you can do it, or you can't. But wobbly progress and grins come amazingly fast: some gentle turns, control - almost - and growing confidence, egged on by enthusiastic advice: "Just aim to the left of the cow!" "Aim" may be putting it a bit strongly, but in no time at all you can vaguely steer the thing.

Before any snowboarders get all cocky and head off to mountainboard from the top of Helvellyn in high summer, the key difference between this and the snow version is that edging, to traverse a steep slope or to brake, is impossible, which makes dumping speed during a turn out of the question - you carve it or you wipe out. Total commitment and total nerve take you through the fall line, accelerating as you go. The only way to learn is on a gentle slope, not more than about 5mph worth. If this doesn't sound much fun, bear in mind that this particular 5mph feels like 50.

Higher speeds, more concentration and severely gritted teeth lead to fast, swerving, linked turns. It happens so quickly, perhaps 8mph now, and the faster you go, the less you want to fall or leap off. Trusting the board to turn is a game of chicken - all you want to do is stay upright, but then you'll fly, ever faster, straight downhill.

Which brings us to the final point: a smooth, obstacle-free run-out. Make sure there is one.

What you need and where to get it

Outback mountainboards from Cunning Stunts (01722 410588) in Salisbury, and Snow + Rock. Cunning Stunts also hires out boards and protective equipment for half-days, full days and weekends, starting at pounds 10 for the board for half a day and pounds 5 for protective equipment. The company also gives impromptu free weekend tuition in the local hills, with all equipment provided, so you can try before you buy.

Boards cost pounds 299, pads for elbows, knees and wrists pounds 13 per pair and a helmet around pounds 40. Boards designed for similar purposes but with four wheels also exist. The three-wheeled variety is much easier to ride, apparently, so steer clear of any other type.

Skateboarders and in-line skaters may already have appropriate protective equipment and skills, such as balance and co-ordination, but don't let that put you off - it's fun at any level. Also fun, for onlookers, is the all-in-one waterproof "jelly-bean" worn by some of the best riders; it gives protection from mud and worse. Beginners should wear the oldest and toughest clothes they possess.

Access

Mountainboarding is a new sport, so you make your own rules, riding where you can until someone stops you. Lots of common land, bridleways included, makes ideal terrain, though it remains to be seen whether enough boarders will ever amass to make access the kind of contentious issue it is for mountain bikers. Though the tyres are knobbly, the lack of real brakes means that even soft ground doesn't cut up too badly.