Hello, just started running and came across the C25K plan, however I gather it's more intended for free running rather than treadmill running (what i'm using at the moment, I live in a notoriously hilly area!) due to the short running/walking intervals which would be hard to change that quick on the machine in terms of adjusting the speeds. At the moment I can do a 5 minute walking warm up following by 15 minutes running non-stop, to the tune of about 2.5k. Should I just carry on as I am? I tend to go 3 times a week and add an extra few minutes on each time.