A few years ago, I completed C25K and was a regular runner (usually 4x/wk), and I had just started marathon training when I was in a bike accident and messed up my knee pretty bad. I tried to start running again about eight months later, but my knee still wasn't right and I couldn't get into the physical rhythm of running; it didn't make me feel good anymore, so I decided to set it aside for a while and focus on other kinds of exercise.
My knee is (mostly, when it's not cold out) better now, and I'd sort of like to start running again (probably starting with C25K). The only issue that I'm having is that I'm now only working out 4 days per week (non-negotiable for personal reasons), and I don't really want to spend three of them doing the same thing.
Do you think that I can build back up some of my running fitness/stamina if I'm only doing it once per week (with three other days of cardio in the form of walking/cycling/fitness videos)? Or would I be better off just letting it go and waiting until I reach a time in my life when I can commit to more?