Gamboised Cuisses were padded armour leggings worn under armour to provide a cushion between flesh and metal. These are the legging equivalent of the aketon for the thigh. They were introduced by about 1220 CE.
When worn under maille chausses, the gamboised cuisses would often have had lacing points to prevent the maille leggings from shifting. When worn under plate armour, the cuisses may have had small patches of maille laced onto the crotch and the back of the knees to augment plate protection without sacrificing mobility.
Gamboised cuisses could be covered in rich materials such as silk or velvet and could be embroidered. This would indicate that at least some of the time, they were worn on the outside of other armour)
Gamboised Cuisses in the SCA
In the SCA few fighters bother with gamboised cuisses, as they can be very hot and uncomforable, and SCA safety rules do not strictly require them.