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FT data journalists analyse races that allow - or ban - drafting to assess impact on results

Should drafting be banned in the bike leg of a triathlon? That’s the question raised by an article published in, of all places, the FT Magazine.

Last week the paper used data from the International Triathlon Union’s World Series to try and assess the impact of an athlete’s ability in the three disciplines – swimming, cycling and running – on the overall result.

They found that in cycling, competitors tended to be closer to the fastest time in that segment, grouped in clusters, than they were in running, where they were more strung out along a line.

They concluded that doing well in running was crucial to winning medals – but now say that was an incorrect conclusion.

It was pointed out to the FT that the data was taken from an event in which drafting of other competitors is permitted in the bike leg – effectively “resetting the clock” for competitors who arrived at transition ahead of the run in a single group.

So this weekend, for comparison, data journalists John Burn-Murdoch and Gavin Jackson had a look at the data for the bike leg of a triathlon in which drafting on the bike is prohibited – last year’s USA Triathlon (USAT) National Championships for the 24-29 age group.

What they found was that in both cycling and running, the results played out “more organically,” as the scatter charts here (registration required) demonstrate.

They say that “without the splintering of the field during the cycling phase, athletes enter the running leg in a steady stream, making for a more balanced overall race.

“Whereas when drafting is permitted, gaps develop and widen so quickly that most athletes who miss out on the main group in the cycling will never get back during the third stage, however well they run.”

According to USAT’s rules,

Drafting – keep at least three bike lengths of clear space between you and the cyclist in front. If you move into the zone, you must pass within 15 seconds.

Position – keep to the right hand side of the lane of travel unless passing.

Blocking – riding on the left side of the lane without passing anyone and interfering with other cyclists attempting to pass.

Overtaken – once passed, you must immediately exit the draft zone from the rear, before attempting to pass again.

A variable time penalty applies for any infringement.

Slovakia's Richard Varga tails Team GB's Stuart Hayes at London 2012

Here’s the views of Mat Brett, road.cc’s resident expert on the multi-disciplinary sport and former editor of 220 Triathlon.

“What John Burn-Murdoch and Gavin Jackson say is pretty obvious to anyone who has been involved in triathlon for any period of time.

“Drafting is illegal in Ironman events and in the vast majority of age-group races but it is permitted in top-level ITU (International Triathlon Union) racing.

“The reason that drafting is legal for ITU pros is to make for a more spectator-friendly sport. It becomes more of a race and less of a time trial. That’s deemed to be better for TV coverage, and the governing body obviously wants that to promote the sport.

“If you want to do well as a pro in ITU races you need to be a good swimmer in order to get out of the water among the leaders and into the first pack on the bike.

"You can afford to be relatively weak on the bike, sitting in and not doing any of the work at the front. Even a strong biker is unlikely to be able to chase down that pack if they’re late out of the water. It’s virtually impossible if they’re working alone or in a pair.

“The chances are that the first bike leg finishers will be in a large group so everything is decided between those athletes on the run. A strong runner will sometimes come through after finishing the bike leg in the second group, but they’ve obviously given the first group athletes a head start so it’s a difficult task.

“Of course, it does help if, like the Brownlee brothers, you’re strong in all three disciplines.

“In age-group racing and Ironman events there’s no drafting. If you’re going to be strong in any single discipline make it cycling because that takes up the biggest proportion of the race time (up to about 50%, depending on race distance).”

Born in Scotland, Simon moved to London aged seven and now lives in the Oxfordshire Cotswolds with his miniature schnauzer, Elodie. He fell in love with cycling one Saturday morning in 1994 while living in Italy when Milan-San Remo went past his front door. A daily cycle commuter in London back before riding to work started to boom, he's been news editor at road.cc since 2009. Handily for work, he speaks French and Italian. He doesn't get to ride his Colnago as often as he'd like, and freely admits he's much more adept at cooking than fettling with bikes.