You've swum 1500m in open water as fast as you can; just the 40km bike ride and 10km run to go, then. Tough stuff, this triathlon. Peter Conchie learns how to coax his muscles into toeing the line

Preparing for your first triathlon can be a lonely pursuit. It is a solo sport that demands many hours of hard training to master its three elements of running, swimming and cycling. In terms of commitment, preparing for a triathlon can be compared with a full-time job, whereas gearing up for a marathon is like attending an evening class.

Despite the effort invol-ved, triathlon is one of Britain's fastest-growing sports. According to the British Triathlon Association (BTA), around 400 events a year are staged in Britain, with total entries of 100,000.

A colleague, David Greene, and I recently attended a training day aimed at first-timers to the sport who are competing this year in events in Blenheim and London. I was there under false pretences, having somehow survived in London last summer, while David was preparing for his first event.

Competitors at the London Triathlon have a choice of distance. The most popular is the Olympic, which consists (in this order) of a 1500m open-water swim, 40km bike ride and 10km run, and the Sprint, for which these figures should be halved. Anyone tempted by the masochistic Ironman events should roughly multiply the Olympic figures by four and look towards the Ironman UK Triathlon, an event that finishes with a marathon.

The training day took place at Dulwich College, the educational establishment whose famous old boys include authors Raymond Chandler and P G Wodehouse. As if in tribute to their alma mater, during the course of the day our collective efforts would lurch between comedy and something from the pages of a thriller.

Our cycling expert was Richard Hobson, a former professional triathlete and the coach of Julie Dibens, an England international who competed at this year's Commonwealth Games in Melbourne. As we sat before him on low school benches, he gamely fielded questions on a bewilder-ingly wide range of subjects. He had advice on how to gauge your correct bike size and how much to spend on a new machine (unless you are a professional athlete, more than £1,000 is not worth it). There was even a deeply impressive demonstration, reminiscent of a West Country David Blaine, of how to change a flat tyre without using tyre levers or a bike pump.

The strangest question (closely followed by one from a man in the second row about whether he should shave his legs) concerned onboard urination. In the Olympic distance, an average competitor will take between an hour and 90 minutes to cycle 40km, around 25 miles in old money. If the urge strikes, what should one do, the questioner wanted to know.

The advice from Richard, to borrow a phrase from a leading sportswear manufacturer, was: "Just do it"; no one will notice as you will be going fast enough, but even if they do see something, they will think it is sweat.

Two wheels under our belts, it was off to the running track, where our BTA coach, Julie Liversedge, took us through some warm-up exercises before a session on technique. Glowing after a vigorous game of stick-in-the-mud, we performed some alternate buttock clenches and then tried to persude our legs to rediscover their - in my case estranged - fast-twitch muscles.

As we high-kicked in formation across the Astroturf with around 100 other more co-ordinated people, I could see the photographer's shoulders shaking with mirth, a fact that I hoped would prevent him recording the moment. The session concluded with three sets of two laps of the running track, during which we were encouraged to learn how to pace ourselves.

As the day wore on, faces that had been previously etched with anxiety became more relaxed. After lunch, there was a talk about hydration and nutrition, and gradually the prospect of a three-hour race seemed less daunting.

One aspect of triathlon that didn't feature in any of the talks, but seems to come naturally to most competitors anyway, is the importance of hiding your light under a bushel. Previous experience should be stealthily underplayed, and any evidence of actual talent, such as certificates or schoolboy representative honours, should be kept to yourself.

Thus, before the running session, my colleague David had declared himself "useless", and before the cycling stint he confided that a childhood accident while riding his Raleigh Chopper had left him wary about two-wheeled transport. The impression was of man lacking both confidence and ability. In the pool, though, I discovered that I had been had.

Coach Dan Plews asked us to rank ourselves in terms of swimming ability, and there, in the second fastest of six lanes, David glided along like a shark. If you can imagine a shark wearing a wetsuit. In contrast, my own attempts at aquatic self-improvement suffered a setback when I missed the first 10 minutes of the pre-swim lecture after I put my wetsuit on inside out. Following some rather technical advice on stroke efficiency and breathing - most of which passed me by as I peeled off then squeezed back into my rubber companion - we were let into the water.

The session was intended to recreate that claustrophobic fish-farm feeling that comes during a mass open-water swimming event. As we thrashed up and down, very often on top of one another, the finer points of freestyle went out of the window. But an equally important lesson was being learnt: that of looking after yourself.

The session concluded with us all practising "transition", the awkward art of swapping between disciplines. James, the demonstration swimmer, swam two lengths of the pool, then jumped out and whipped off his wetsuit in double-quick time, as if in preparation for the 10km run. He managed to keep his trunks on and got a round of applause.

As the day ended, new companions wished each other well and dispersed in varying states of disrepair and exhaustion. While most of us were not yet ready to take our place on the starting line, in a few intense hours the thought of completing a triathlon had become a marginally less daunting prospect.

Entries for the Blenheim Triathlon ( on 20-21 May and London Triathlon ( on 5-6 August are closed, but spectators are welcome. Places are still available for The Ironman UK Triathlon ( at Sherborne, Dorset on 20 August. For more information about triathlon: