I have been doing this back and biceps workout for the past 4 weeks, working on improving my weights at the same number of reps. I will continue for the next 4 weeks and then switch up the workout. It is designed circuit-style meaning that you move from one exercise to the next with little rest in between. I rest as needed, as there are no structured rests. My biceps tend to get tired more quickly, as does my grip so I usually take 45-60 seconds between biceps movements (3rd circuit). The whole thing takes me about 35 minutes. Good luck! ox Jill