Genetics play a role, but it can be done with very, very gradual increments in weekly mileage, perhaps over the course of years. The "add no more that 10% rule

Genetics play a role, but it can be done with very, very gradual increments in weekly mileage, perhaps over the course of years. The "add no more that 10% rule per week" is even too aggressive over the long run. You have to give your legs time to adjust to higher mileages.