A lot of leg and back excercises are compounded movements that work both parts of the body. For example good mornings and straight leg deadlifts. I do GM's on back day and SLDL's on leg day. My question is, does it matter on what day you allocate these workouts?
IMO, the important thing is that you keep them separate from eachother with as much space as possible. Beyond that, the advantages of rearranging them and concerning yourself with specific exercise pairings are minimal at best.
are you asking me? Cause I'd answer that with a question: how far apart CAN you put your legs and back days? 2 or 3 days in between is as far apart as they can be and still be in the same week. Many people find that they respond just find deadlifting heavy every other week and focusing instead on their squats.
You can split them up, but you are still going to be using both the back and the legs, depending on your own proportions. Instead of splitting, I simply use different exercises. When I did all lower back in one day, I found my lower back would be too sore to be comfortable on squats. Since I always involve a lot of lower back with my back squats (due to my proportions), I follow up with RDL's which will work the legs (hamstrings) more than the lower back when compared to SLDL's. On deadlift day I follow up with front squats so I do not have to involve the lower back as much after heavy deadlifting. Example: Day 1: Squats Romanian Deadlift Day 5: Deadlift Front Squats
