Welcome to your Essex Marathon Plan! Challenge yourself to this great Marathon in Essex. This is a flat and fast course with tarmac, traffic free running around the former RAF Debden Airfield. The course is designed in the shape of an aircraft in honour of so many RAF and USAAF who were stationed here over the years. An iconic event! This is an 18 week intermediate training plan 80/20 training is highly effective and you spend 80% of your time working out at a low intensity and 20% at a high ...