Running portraits

This year's Brussels 20km race attracted around 40,000 runners, who completed the circuit through the city's boulevards and parks in sweltering heat. At around its half-way mark the course runs throught the Bois de la Cambre, close to where I live, and I was there as the first contestants arrived. Soon, the road was packed solid with contestants.

Like all the best activities in Brussels, the 20km mixes participants and spectators from Belgium's Flemish-speaking and French-speaking communities with foreign residents and visitors, and it is conducted with universal good humour.

I love photographing people as they run. Their faces are concentrated and intense, expressing aspects of themselves that would often be hidden in posed portraits. But it is technically and emotionally challenging – I only had a second or two to select each face and focus, swinging the camera to track it as the person passed. I tried to acknowledge everyone I photographed, and exchanged smiles and a few words with many of them. At one point, firemen had tapped into the mains water supply to set up a makeshift spray, and I captured some fine expressions of shock as cold water drenched hot bodies.

After a couple of hours, I cycled across town to the Cinquantenaire where the race had started and where many of the people I had photographed were now arriving at the finish. I managed to speak with a few of them. I gave Claude my card and have since sent him the portraits that I took of him.