Rules - ceiling height of the approach

[andrej]

I was looking at some of the indoor tracks throughout the world (the small ones) and was wondering if there is a rule on how high the ceiling has to be in the area of approach? If there is no rule, could it be less than 10 feet - then nobody could carry the pole during the run, but the conditions would still be regular? In Slovenia we have an indoor track that has ceiling at about 9 feet in the area of approach and then gets higher for the vault pit, but I never jump there cause it bothers me too much. Is this something that is missing in the rule book, or is there a rule that I missed?