The marathon is a long-distance road running event of 42.195 km (26 mile 385 yards or 26.21875 miles).
The length of a marathon was at first not fixed, since all that was important was that all athletes competed on the same course.
The exact length of an Olympic marathon varied depending on the route established for each venue.
For most runners, the marathon is the longest run they have ever attempted.
Many coaches believe that the most important element in marathon training is the long run.
Usually recreational runners try to reach a maximum of about 20 miles (32.2 km) in their longest weekly run and about 40 miles (64.4 km) a week in total when training for the marathon.
More experienced marathoners may run a longer distance, and more miles or kilometres during the week.
Greater weekly training mileages can offer greater results in terms of distance and endurance, but also carries a greater risk of training injury.
Most male elite marathon runners will have weekly mileages of over 100 miles (160.9 km).