well 2 on 1 off would be considered a 4 day split just by the way. but an effective split would be:
monday: upper body, mostly push
tuesday:lower body, lower back
thursday: upper body, mostly pull
friday:lower body, lower back
you can add cardio and abs in if you want on off days, and a couple lower back exercises for you would be a romanian deadlift or back extension. hope this helped.