Good points. I just really want to do more than just tennis. 5ks are a culture shock for me in terms of getting up way too early on a weekend and running a fairly long distance. That is out of my comfort zone which is a good thing. I also believe I will lose weight from this. I know a lot of people who lost weight simply from running and nothing else.
I do like HIIT and I do it via jump rope before I lift.
Please help TT Member BruceD get a wheelchair so he can play tennis again - http://tt.tennis-warehouse.com/showthread.php?t=496820