Verily, I was shaking in my armour at jousting session

Five hundred years on, medieval sports are enjoying a renaissance. Oliver Duff tried his hand

"Many knights died from internal bleeding, not from their armour being pierced," Rob Martin says, as we walk on to the jousting training range. It's not the most reassuring thing to hear minutes before he will climb on his charger and gallop towards me, lance poised to strike. My 70lb suit of armour clatters with nervous energy.

I'm at a 15th-century-style knights' training school at Druid's Lodge, near Stonehenge, to receive lessons in foot combat and the Middle Ages art of jousting. The brief is to experience first-hand this sport of gentry, reborn after a 500-year hiatus.

Popular interest is growing: crowds at shows are rising and companies now offer a day of medieval combat for stag and hen parties, office team-building exercises, or those who simply want to burn off a little excess aggression. This summer, for the first time, there is an organised league.

Four teams of knights, squires and valets - a motley crew of real-world IT consultants, artists and forklift suppliers - are fighting each other during six weekends of colourful pageantry at castles and stately homes around the country, in English Heritage's "Knights' Tournament".

It is the only competition of its kind - most medieval shows have choreographed combat - and audiences are promised "bleeding gums, bone breaking swords and 50mph collisions".

Mr Martin, 36, an expert jouster and swordsman, is the marshall (referee). "It's back to the full-bore violence and breaking bones of tournamenting," he says.

"Concussion and whiplash are fairly common, as are broken fingers. I've seen a dislocated jaw and someone with their throat open, bleeding profusely from a blade wound.

"Whereas the fighting you see in films such as Gladiator or Star Wars is choreographed dance, what you get here is genuine competition. Each fighter has his own agenda and it can get sloppy. It's a bit like boxing in that regard - except with the poleaxe, warhammer and mace." I imitate his footwork and he clobbers me with his sword for good measure.

As for the joust, it is "the most extreme sport you can do on a horse," says Steve Mallet, 38, the competition favourite. "It's soul-seeking. You and one other guy put yourselves up with no defence whatsoever. You have to use your brain to conquer your fear and place your trust in the team: you, your horse and your armour."

The worst thing you can do is shut your eyes, even for a split second, missing your onrushing opponent. A closing speed between 50 and 70mph is transferred through the end of a two-inch-thick wooden pole, causing severe damage to armour, which costs up to £12,000 and takes six months to make. It is a sobering thought on a sunny afternoon, as I sit on the dummy horse waiting for my opponent to charge. The invincibility you felt when putting on the armour gives way to mild claustrophobia. Senses are dampened: it is difficult to hear or see through the thick helmet. But the slit in the visor allows me to watch horse and rider charge toward me. His clean strike knocks me backwards - I'm only able to hold on because my hands are free - and the lance splinters on my breast plate. There's a great adrenalin rush from being hit so hard.

The new tournament hopes to feed a revived public appetite in such clashes. Medieval knights drew crowds of 60,000. More than 8,000 people are expected at Audley End in Essex this weekend for the next round, and 20,000 will attend the final at English Heritage's Festival of History, Kelmarsh Hall, Northamptonshire, in August.

Early indicators are that jousting may take off. The companies that supply riders and horses for shows and filming report a surge in interest.

"Its popularity is growing," says Sam Humphreys, founder of the Nottingham Jousting Association. "We're now booked out every year and have crowds of 15,000 at big festivals."

Further information is available at www.english-heritage.org.uk/knights