Thanks for info on the medical certificates! I would never have considered this. I don't do very much road racing so I typically don't have consider pre-qualification issues. The smaller trail races (field size not distance) in my area back in the States are almost community events, which is really cool because they are very social. Lots of trail rash, twisted ankles, some jammed or dislocated joints, stressed knees, runners groaning by the trail from full body cramps (donate the appropriate electrolyte tablets), or simply out of fuel (bonk)...but nothing very serious. I did notice the the aiguillesrouges race only has a couple aid stations. That does make the race harder and would require more forethought (and possibly a running buddy for safety sake). A medical certificate may be well advised in this case!