Like all muscles in your body, you can perform back exercises up to three non-consecutive days a week. If you're lifting heavy weights — enough that you can only complete six to eight repetitions — you'll need two or more days of rest before you perform the exercise again. However, if your goal is to gain endurance and strength, stick with one to three sets of 12-16 repetitions lifting a weight that fatigues your muscle in that rep range. ~ Berceste