How to choose training fiels for marathon

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　　Choose a straight and level race track. An ideal track is solid but not too hard. It should be level without holes on it.

　　1) Sideway

　　Unless it is crowded in other place, do not run in sideways. Cement and stone sideways are much harder than pitch roads. And sideways are often uncontinuous, with crossroads and folk roads. What's worse, many sideways are not level so that you should jump up and down.

　　2) Grass

　　People generally think Golf pitch or country roads in open fields are good for running. But the surfaces there are not level which may cause tiredness and even injury of muscles, feet and tendo.

　　3) Race track

　　Race tracks of the sports fields are solid but not too hard which are ideal places.

　　But which track is better, indoor or outdoor? Indoor tracks are not a good choice, because they are too short. Frequently turning back will increase friction in the knee. And injuries are more likely to happen.

　　4 Beach

　　Beaches are not ideal places. Generally speaking, soft sand makes you stand unsteady and cause tension of the muscles. If you have no other choice, you'd better train when in ebb. Sands is more in the beach after ebbs and it is open.

　　5 Cinder road

　　A small path coverd with cinder is a ideal track, because it is level and without trails by cars. Even in raining days, it won't be slip and muddy.