How to measure a marathon course

The IAAF World Half Marathon Championships come to Birmingham at the weekend, but have you ever wondered how a road race course is measured? spikesmag.com caught up with Hugh Jones, an expert in this area to find out more.

Now, if course measurement doesn’t particular strike you as the most glamorous job in the world, you are probably right.

Why? Well firstly they carry out the task on a bike – a push bike. Hmm, nothing remotely cool there. And then the distance is invariably covered in the dead of night, so many course measurers are a nocturnal breed.

Slightly eccentric it may be, but Hugh Jones, the 1982 London Marathon winner and now one of the world’s leading IAAF course measurers, believes most runners have at least a casual interest in this area.

“GPS (Global Positioning System) has become a byword for runners measuring their own courses – inaccurately by the way,” says Jones. “Even before my serious athletics career ended I was interested in learning how to measure a course,” he explains. “I was quickly able to understand what I was doing and find it very simple and logical.”

After retiring from serious athletics in 1994, he quickly graduated to measuring the London Marathon course and later carried out the same role at the 1998 European Championships in Budapest and 2000 Sydney Olympics.

As a member of a small team he is one of the world’s elite course measurers, but after spending much of his professional career on two feet he now devotes a large chunk of his time to travelling on two wheels.

His measurement bike is fitted with a mechanical counter inserted between the front fork and wheel, which counts numbers and those numbers represent fractions of a revolution.

All that needs to be done is to ride the accurately-measured length of road to calibrate the bike’s wheel count with counter readings, and then ride the road course from start to finish.

As the calibration gives a number of counts per metre, the total counts for the road race course can easily be converted into metres to determine its length. Simple.

“I start at a reference point and I’ll go to lamppost one, say on Dudley Street,” says Hugh, who measured the World Half Marathon course in Birmingham. “When I get there I know I’m at about one kilometre and I take a reading there. When I’ve recalibrated and everything has evened out, I’ll be able to calculate how far into the course that lamppost is. It might be 994m into the course. I then give the race director a big long list for every kilometre.”

He says he approximately covers 10km in about one hour – meaning measuring marathon courses can take upwards of four hours, often in the early hours.

So does this present any problems?

“Well, there are disadvantages and advantages,” he insists. “The advantages are obviously less traffic, but when I measured the Birmingham half marathon course the disadvantages are that part of the route passes through Cannon Hill Park which at night is in complete darkness.”

Thankfully, he admits surviving that experience without incident – however he has been prone to the odd accident, when measuring late at night.

“I was in Austria where tram tracks are a big problem and my wheel caught the tram track,” he explains. “It was nothing serious. I had to start the route again, although it was only a kilometre into the route.”

The bike also allows Hugh to take the shortest route in the same way that runners are free to cut tangents on the road. Even the blue line used on more marathon courses is only an indication of the shortest route possible – simply because the machine used to lay the paint on the road cannot take corners as closely as a runner or a bike.

Hugh has discovered discrepancies in road race distances in anything from a few metres to two miles, and it is his job to then 'cut and paste'. Working with the race director he will then add or subtract the distance from either the start, finish or somewhere in the middle.

He has a whole range of options available to him. He may decide to run a slightly longer or shorter way round a roundabout or to widen or shorten a particularly corner to reach his target.

However, he insists, the exact distance of a course is impossible to measure: “Most people do not understand there is no such thing as a precise measurement. There is always an error. We have found it is about one metre in a kilometre. You try and factor this to make sure the distance is not less than the stated distance, but it might be a little bit more. You can only be sure it is accurate to a certain degree.”