Tuesday, August 18, 2009
163.4. (a) If an athlete is pushed or forced by another person to run
outside his lane or on or inside the kerb or line marking the
applicable border, and if no material advantage is gained, the
athlete shall not be disqualified.
(b) Likewise, an athlete shall not be disqualified if he
(i) runs outside his lane in the straight, and no material
advantage is gained or
(ii) runs outside the outer line of his lane on the bend, with no
material advantage thereby being gained,
and no other athlete is obstructed.
IAAF competition rules 2009
(I had to check this for my own peace of mind~ the race in question is last night's Women's 100m final.)