What does your "leg workout" look like?
What about your "cardio?"
How long have you been using this setup?
Maybe you could take a different approach to your sessions for awhile, sort of stressing conditioning, to combine legs and cardio.
I've been dragging the sled lately. At first I thought it would be sort of like cardio. It's really more like doing a bunch of calf raises, lunges, leg extension, pull thru's and rows all at the same time, for like 40 reps at a time.
I've really been enjoying it.