Hey, I really appreciate the site. I'm just starting to work out again (did the Level 4 - Day 1 today). I've worked with weights regularly in the past and do pushups and crunches occasionally but haven't stuck to a workout plan in a while. I'm not overweight and in decent shape, so I'm working on building muscle rather than weightloss. My idea is to follow your plan and run on the off days (4-8 miles) and then take one day of rest from both each week. I was also thinking I would incorporate a core workout on one of the days. I realize the plan described here does use the core, but I want to target it a little more. Would it be better to do this workout on my pushup/pullup/squat day or my running day? I was thinking it would make more sense to do it with the pushups/pullups/squats so that my core can rest more on my running days. Thanks!