For most people, the long, idle summer days we enjoyed during vacation as kids are a faded memory. Now there is more to do than ever. Softball and beach volleyball leagues, street festivals, concerts, bike trips, barbecues, pool parties, and if you're a parent, all kinds of sports and activities to chauffer the kids to. That's a lot to compete with a daily running schedule, and many people just can't fit a run in every day. Yet some people thrive on a minimalist schedule of three days a week, to the point where they can be quite competitive.