The Windsor runner was cleared of taking nandrolone by UK Athletics in July, thanks to the Aberdeen study.
Ohuruogu, a 23-year-old British runner, was cleared to compete in next year's Beijing Olympics after the ruling by a sports arbitration panel.
The runners' sand was cleared to make a space, and the spectators came down from the embankments to stand at a respectful distance from the fighters.
Last year the athlete, known as the "blade runner" because of his prosthetic limbs, was cleared to run overseas after appealing his bail terms, but chose not to while he focused on his murder trial.
The runner served a six-month ban but was cleared by UK Anti-Doping (UKAD) of knowingly cheating.
After Round 1, the front-runners were clear.
Without insurance, safety fences, "catchers" at the bottom of the hill to stop out of control runners, or any assurance the course had been cleared of undergrowth, nettles and brambles, a smaller than usual field of competitors took part.
* South African runner Caster Semenya has been cleared to return to track and field and compete as a woman.
The whistleblower and 800m runner Yuliya Stepanova had also been cleared, but now misses out because of the IOC ban on any Russian athletes who have previously served a suspension.
On Monday, during her first debate as the perceived front-runner, it was clear that the serene, soft-spoken senator and former environmental minister had moved into the cross hairs of Rousseff and Aecio Neves, the candidate for the center-right Social Democracy Party of Brazil, or PSDB.
