I am actually doing this right now as I was recovering from some tight calves/shins a couple of months ago. I am currently running 2 days, and doing elliptical 1 day to replace my 3rd run day. I also replaced all of my running with elliptical workouts a couple of years ago when recovering from a stress fracture, and while it is certainly not the same as running, I was surprised how little fitness I lost, and how easy it was for me to ramp up miles once I started running again.<br><br>
Not sure what the conversion would be, but I think you would have to put in slightly more time on the elliptical to equal the same effort of running - of course that depends on what resistance you have it set at, but I try to use a lower resistance to mimic a similar cadence to that of running (if that makes sense....)<br><br>
There are certain running muscles that just don't really get a good workout on the ellip, but overall I think it maintains your fitness really well. Aquajogging would probably have been the best replacement for running, but it just is not convenient for me to get to the pool any more than I already do.<br><br>
I think people just have different experiences with this, but mine was pretty positive so when I have the slightest hint of a running injury, I hop on the elliptical!