Source I don't profess to be an expert at running. And one thing I've never been is a long-distance runner. When I say long-distance, I'm being a bit generous to myself. In truth, I'm not even a medium distance runner. I did a 10K back in April (yay for the Vancouver Sun Run!) and that was the longest I have ever run. 10Ks are my marathons :). I'm happy to do one every now and again but prefer to stick to 5Ks if I have the choice. I haven't been running much lately, as I injured my knee earlier this year and I have been advised by many doctors to avoid running and pursue other forms of exercise which are gentler on the body, so I tend to get my cardio from intense flow yoga classes or from incline walks on the treadmill or intervals on the gym's cardio machines rather than running.