Why should you incorporate recovery runs in your training?

In recent years, there has been considerable controversy in Australia regarding surgery for degenerative tears of the medial meniscus. Critics cite epidemiological studies to support their view that such surgery is of no benefit and in many cases probably harmful (Buchbinder,R and Harris,I, Editorial, Medical Journal of Australia;197:364-5, 2012). And yet, knee surgeons continue to perform large numbers of partial meniscectomies in active people over the age of 40, adamant that in most cases patients are much better off than if the surgery had not been carried out.