Martyn Rooney has admitted that his efforts in the heats played a key role in his sixth-place finish in the 400m semi-finals at the World Athletics Championships.

The 28-year-old, who was given the honour of captaining the British team for the meeting in Beijing, recorded a personal best time of 44.45 seconds to progress yesterday, but he was never in contention for a spot in the final after tiring in the closing stages of his semi-final.

"I really wanted to make the final, that's what I came here to do. I had a great opportunity to do it but it was just not there," Rooney told BBC Sport.

"I ran a personal best yesterday and if I could do that again I would be OK but it just takes a lot out of your body. I came here to fight for my place and for my team but it was just not good enough."

There will be a British representative in the final after Rabah Yousif clocked a new personal best to qualify as quickest loser.