many runs 100s mile a week and don't have knee problem

长跑（比如马拉松）会伤关节 is a myth.

The basics are:

1) run within your ability and increase weekly mileage very graduately, not more than 10% each week.

2) get profesional fit for your running shoes

3) proper warm up and cold down - make sure you do stretch after the run while muscles are warm

4) build leg and core muscles - many knee problem comes from weak muscles

5) watch your weight - don't put too much stress on your knee

6) run a variable speed and hills - don't just run on flat

7) build in rest days

8) see chiropractic service regularly

etc.