I often find myself falling into the same pattern. I start upping my cardio, I realize that running is hard to get back into and I end up doing the elliptical instead. This is how I feel about running.
I rationalize this decision by telling myself that its low impact, easier on my joints and back and still provides the same quality of cardio. But at the end of the day the elliptical does not come close to running.
There’s a lot of people who argue both sides of this. I’m not sure who’s right but I can personally say that I find running much harder than the eliptical. And if I’m training for a race, I think it’s more beneficial to train on the treadmill since I won’t be ellipticalling to the finish line.