For spectators, there are few sports more exciting than moto-cross. Take 40 riders, add a selection of man-made obstacles and whatever the weather conditions, you're guaranteed a spectacle. For the adrenaline junkie, there's a chance to see the experts in action at this year's UK championships

Stamina is one of moto-cross's main requirements - and that's just for the spectators. For the competitors, add liberal amounts of speed, skill, and a large dose of personal risk-taking, and you have the main components of the sport.

Dave Smith has been an agent for moto-cross riders for 20 years and has been involved with the sport for more than 40 years. "There have been lots of changes in the machinery used over the years," he explains. "Design of the bikes, and the power they now have, have both changed dramatically."

Moto-cross bikes are capable of more than 100mph, but most tracks (each of which are individually designed), have various man-made obstacles, so top speed is not all that important.

It's also a gruelling sport. Top riders spend seven days a week riding, training and travelling. There are 16 Grands Prix held around the world, in addition to 12 other international races in the 125cc and 500cc classes.

"You can start from as young as 6 years old at 50cc," according to Smith. "It's all carefully controlled by the Auto-Cycle Union (ACU)."

Riders then work their way through the youth divisions. By the age of 15, they are classed as adults and can ride a bike of up to 125cc. After that it's unlimited, from 500cc and above.

Dave Thorpe has been riding motorbikes since he was three years old. He was World Moto-Cross Champion in 1986, 1987 and 1989 so, in his case, practice obviously made perfect. He now manages the Cat Honda Team which competes in the 125cc class.

"The first thing that catches everyone's imagination is the start of the race," he says. "Unlike road races and Formula 1, there's no grid start. Basically you have 40 riders on one row.

"The sight of them dashing 100 metres, all trying to take the lead around the first corner, is an amazing sight. Moto-cross is all action."

With the races involving 40 riders and lasting 45 minutes, surely there must be plenty of crashes

"You need to be mentally strong and in top shape, as the season is quite long but you'd be surprised how few crashes there are at the start of races.

"In general it looks far more intimidating when you're watching than when you're actually on the bike trying to get around the course."

The British Championships start on 1 March in Swindon. Held over eight rounds, races are held all over the UK before returning to , for the final race in Swindon, on 18 October.

As well as featuring the cream of British talent, the races also feature wild card entries from across Europe.

"Spectators are going to get damned good value for money as they can go to a British Championship for pounds 6, for a whole day's entertainment," insists Dave Smith.

Moto-cross is pure racing and pure adrenaline, but it's probably best to watch the professionals before splashing upwards of pounds 300,000 for your own team.

Call the Auto-Cycle Union on 01788 540519 for a free fixtures diary and additional moto-cross information