"Little or no training should be done on the bitumen or concrete roads.I am one who does not believe that the body can ever get used to running fast with free movements if it is trained on hard artificial tracks and roads.It is bad enough that the athlete has to race on such mediums: to me another illustration of how far intellectual decisions made by officials differ profoundly from the conclusions arrived at by serious experimenters and knowledgeable performers.The marathon man must watch that his musculature does not respond to his type of training by a shortening of his stride and the development of a restricted gate that almost completely inhibits the possibility of being a a free mover with commensurate high speeds." Comments by Percy Cerutty.
And you thought that running on the roads and hard tracks only caused undue stress on your knees? As a sidenote,years of running and training on hard surfaces also greatly increases your chance of having back problems.If you desire a long healthy running life you should make it a priority to seek out parks and courses that have hard packed dirt surfaces.
Perc's above comments were made in reference to marathon training.He wanted runners to be wary of the restricted,shuffling gait that is sonetimes adopted by athletes who do alot of long easy runs.It was his desire that marathoners run smoothly and efficiently,maintaining good form.
Interestingly,although written sometime in the late 50's,Cerutty had very definite opinions on who should and shouldn't run marathons.Again,keeping in mind the era and mindset of when this was written,he said those who run a marathon just to finish it "tend to make a burlesque of one of the toughest events in any sport any man can compete in." Whew!