Paula Radcliffe is the one of the best female long distance runners. In this video she recommends easy runs to remove toxins from the body.
Cause of toxins in your body.
If you are feeling sore after running exercise it is because toxins (lactic acid) has built up in your muscles. An easy run can go a long way in flushing it out of your body.
Watch video on how to remove / flush out toxins from your body