Exercise intervals: Rest 30 to 60 seconds between sets. Recovery and Progression: This applies if you do two or three sessions each week. After 10 sessions, you should take a recovery week by doing only one weekly session, or do your weekly routine with only one set instead of three sets per exercise during each session. Warm-up and Cardio: Before each session with at least 20 minutes of aerobic light-treadmill work, bicycle or step machine. Building a slim athletic body is not even as difficult as some people make it be, but you have to work out and you have to push yourself.