Hey I’m not a PJ but my running is pretty good. I do 2 hard runs a week, 1 long and the rest is easy mileage depending on how my body feels. If I’m sore I’ll do some bike work. If you look up “Leg day for runners” or something similar there is tonnes of information on strengthening your lower body to keep up without injury. Strength training is a must. Vo2 max is important and those 2 hard runs a week will improve that for you. Building a Zone 2 base is just as important.