I was running a 5k about 4 times a week about 5 years ago. It started to wear on my knees and had to tone it down. I’ve thought about trying a 10k or half marathon. I’ve started some treadmill workouts to get back up to speed. So far the knees are behaving! I usually run with Nike shorts with bolt in spandex, but added a jock because my bits and pieces tended to bounce too much...plus I like the smell of a sweaty jock and love the feel.