In running, a 4 × 400 meters mixed relay race was introduced at the 2017 IAAF World Relays, and added to the 2019 World Athletics Championships (details) and 2020 Summer Olympics (details). In addition, a 2 × 2 × 400 m and shuttle hurdles mixed relay races were introduced at the 2019 IAAF World Relays. The Match Europe v USA in 2019 had a mixed 200+200+400+800 metres sprint medley relay.