Marathon Challenge For Cambridge Troops
10 soldiers from Waterbeach barracks, near Cambridge, are setting off on a marathon challenge this morning.
They're aiming to complete 10 marathons in five days for charity.
During the 260 mile challenge the team will carry a standard army rucksack, weighing the same as an average four year old child.
The troops are all part of 39 Engineer Regiment, which provides engineering support to the RAF and the army.
Lance Corporal Richard Holmes said: "You have to take into consideration that we're doing two marathons in 24 hours.
That can take up to anything from six to eight thousand calories.
The daily intake a man burns off is about two thousand calories anyway, so that is a lot of calories to make up.
So we can pretty much eat what we want, when we want!"
The troops are raising money for St Dunstan's, a national charity that provides rehabilitation and training to service personnel who have been blinded in conflicts.