The Tug-o-War is technically a Heavy event, but unlike the other individual challenges, this is a team event.

Teams of eight, weighing in at a maximum of 116 stones (725kg) pull a 12 foot rope, remain on their feet at all times and with the exception of the anchor (at the end of the rope) must not put their hands on to the ground. 

Tug-O-War is as much a psychological war of attrition as a physical one with teams waiting out their opposition before an almighty pull on the rope!