I am a visually impaired runner who would like to qualify for the Tokyo 2020 Paralympics. The categories are very strict and I am allowed to run only a few sprint event and the 5000m. I am a long-distance runner and I am very bad at sprints so my only chance would be the 5000m.
The qualification time probably will be 15:40.
I am 29, lean, small and I have been running for six years while focusing on the longer distances - mostly half-marathons (20+ of them) and marathons (10 of them). My favorite race is the half marathon, and I usually complete it in the range of 1:25-1:30. My marathon PB is 3:25.
My weekly mileage varies between 15 miles and 60 miles. I run about 2000 miles a year.
I can run a 10K in about 40 minutes, with a PB of 39:50, while my 5K PB is 19:18.
I have never run a proper 5K or 5000m race, I always considered these as tempo trainings for my longer races. Still I would say I can ran a 5000m in 18:30-19:00.
What do you think, is it possible to improve that much to reach my goal? I have almost four years to do it. Am I too old for this? What books would you recommend reading? How should I change my training compared to the longer distances?