The 20km Road Walk is one of a handful of out of stadia athletics events. 

A 10000m track walk was held sporadically at the Olympics until 1924. After that it became a road race but the distance was changed to 20km and 50km after 1952. The 10km road walk returned briefly for the 1992 and 1996 Olympics as events for women, before giving way to the 20km distance.

The event was introduced at the World Masters Champs in 1977 after an initial distance of 25km was used in 1975. However, it has only been fully established for women from 2007. Prior to that, it was an event put on just for men with the women given the 10km Road Walk instead

The first three finishers per country within each age group count towards the teams. The team ranking is determined by the aggregate of the three times. Where a country does not have three entrants within an age group, they can opt to drop up to two competitors from older age groups down to form complete teams. This cannot be done if a complete team already exists. The decision to do this must be logged by team managers prior to the race (presumably to prevent strategic DNFs by competitors).

Prior to 1991, the teams format varied with options such as points from sum of place, team numbers of 2 or 5 or 10, composite age grades and could differ between grades. It was even permitted to form multiple teams per country in the early years.

Individual 20km walk results are here.