My 16 y/o daughter has developed a concerning problem over the last month. This has happened 3 times and in high school 5k races only, not training. Near the end of the race, 1/4 mile out give or take, she loses the ability to keep running. She describes it as a numbness and that she can't force her legs to work anymore. Additional symptoms are blurry vision, collapsing at the end of the race, not able to sit up for 10-15 minutes, vomiting small amounts after, and twice she has lost control of her bowels during these episodes. Yesterday she actually had to stop 100 feet from the finish line because her legs just wouldn't move anymore. She managed to jog in after she stopped. It looks like she is running underwater when this happens, slow motion. I have taken her to the doctor and cardiologist and they haven't found anything upon examination. Her iron stores are slightly low, but not so much that would be concerning. She is a vegetarian, but has been for 5 years and has run for 5 years also. I really don't know where to turn next, maybe a neurologist. Please, any advice or insight from your experience would be helpful.