Records and personal bests tumbled in the main stadium on Friday, thanks in part to a new track design that harnesses the power of the little toe.
The £1m track features technology that aims to rebound energy from the sideways movement of athletes' feet, including little toes and the side of the foot.
The previous Olympic track in Beijing was designed to maximise the rebound when runners pushed forward and backwards, but the inevitable sideways movement was effectively lost energy, the track designer told the Guardian. Joe Hoekstra, project manager for supplier Mondo, which also laid the track in Beijing, said a special underlay is patterned with rhombus-shaped ridges to increase the track's reaction to lateral movement and is in use for the first time in London.
"Since Beijing we realised we needed to make the material more reactive sideways, as well as forwards and backwards," he said. "We saw that sometimes the little toe touches first and there is a roll over. We have previously provided shock absorption and reaction in the straight line and we have been working on a material that is omnidirectional."
The top of the track has also been made softer than in Beijing to increase its ability to drive energy back into the athletes' feet. "It trashes the notion that hard is fast," he said.
The roof of the stadium was also designed to maximise track speeds. The stadium engineer ran wind tunnel tests to assess the impact of designs of winds at track level and decided on a partial roof to minimise wind on the track.
"We have already had 15 personal bests from the athletes who competed in those five heats and Jessica Ennis set a world record," said Debbie Jevans, Locog's director of sport. She added that the enthusiasm of the crowd could also be helping athletes produce top times. "I doubt that any of those athletes have competed at 10 o'clock in the morning in front of such a full stadium," she said.
