The "double deadlift," also known as a tandem deadlift, is a variation of the deadlift where two people lift a single barbell at the same time. It involves two lifters standing side-by-side, each grabbing one end of the barbell, and lifting in unison. 

Origins and Evolution:

• While popular in modern strongman competitions, the tandem deadlift has roots in powerlifting.
• It's a way for lifters to test their collaborative strength and synchronize their movements.
• The Double Deadlifting League was created by powerlifting champions Larry Pacifico and Mariah Liggett to promote this type of competition.
• It has become a notable event in the strongman world, where athletes attempt to lift massive weights together. 

Notable Achievements and Records:

• The heaviest tandem deadlift ever recorded was 1,915 pounds (850 kilograms), achieved by British strongmen Eddie Hall and Mark Felix in June 2016.
• Other impressive lifts have been made by teams like Jake Marsee and Tyler Obringer (in photo), who set a record of 1,400 pounds at the Arnold Sports Festival in 2019. 

Key Points:

• The double deadlift is a specialized variation of the deadlift that focuses on teamwork and synchronized lifting.
• It has a place in both powerlifting and strongman competitions.
• It allows two individuals to achieve feats of strength that would be impossible alone. 

Note: The history of the deadlift itself dates back much further, evolving from functional movements in manual labor to formalized strength exercises. Early strongmen like Hermann Goerner popularized the deadlift in the early 20th century. However, the development of the double deadlift as a specific competitive event is a more recent phenomenon.