strapping under the boot to stop them riding up? Never worn that type myself so can't say for sure. You may also have a pair of hooks on them to fit over the front boot lace.
The only pair I ever had did indeed loop under the boot to stop them riding up your leg. They were not army ones though. This method was a bit of a pain since they were laces which a) got covered in mud etc since they were under your foot, and b) frayed very quickly if walking over stony or rough ground.