(a) The course must not have a net decrease in elevation from start to finish exceeding 1 part per thousand (i.e., 1m per km).
(b) The start and finish of the race must lay no more than 30% of the race distance apart as measured along the straight line between them, except when it can be shown that the average component of the wind direction at the head of the race (the lead runner) did not constitute a significant tailwind.
NOTE: A tailwind shall be deemed to be significant if it prevails consistently throughout more than 50% of the course during the race.