Hill work for beginners....but what about my knees?

[parklives]

Am a C25K graduate, but am very slow. What to increase my speed so I can do my 5k route quicker (I do 3xtimes a week).
I want to introduce hill work to improve my strength and stamina, and am lucky in that I live in a valley with lots of hills around.
I am concerned about my knees though. at the moment they are fine, but my dgm and dm both ended up in wheelchairs due to their knees by their 60's, and I am worried I have inherited the same knees.

My concern it once I have run up the hill, how do I come down without jarring my knees? I don't want to have to walk down as that will take up much more time, but I feel like I am damaging myself if I try and jog down. Do I just need to pick gentle slopes? Or am I worried about nothing as my muscles are strong enough to protect my skeleton by now?

Most of the hill work I've done involves 'reps' so you run up a bit of a hill and jog down again then repeat this a number of times. The idea is you should run all the reps at the same pace so don't hare off at the start!
I'd start with a gentle-ish slope and try 5 or 6 reps, have a few minutes rest then try it again. It is surprisingly tough >
This way you build up slowly and your knees should be fine.

Going down a hill is very sore on knees. Do loads of squats before you start hill running.