Usain Bolt could run 100m in 9.4 seconds, says Michael Johns

[Skeng DX]

Johnson told Laureus.com that Bolt was "not a very clean sprinter" from a biomechanical standpoint, compared to America's Tyson Gay or Jamaican Asafa Powell.

Johnson cited analysis conducted at the Michael Johnson Performance Center in Dallas.

read more: http://www.bbc.co.uk/sport/0/olympics/18730830