Stretching but achievable goals. That way you get the psychological benefit of achieving your target, but the physical benefit of pushing yourself. And as time progresses and your body gets use to its new uses, those goals get longer.
Think of it like your bike. I don't know how much you ride, but if say your typical ride is 10 miles on the flat, most people wouldn't think of doing a lumpy 60 miler without some build up and would be unlikely to do it in 5 mile increments. It's more likely to be 5, then 10, then 15 etc.