A structure which resists dynamic forces, forming a mounting for a seat of an air transport craft and a seat having such a structure comprising front and rear feet, a front anchorage, an energy absorption device, and a stop mechanism. The front and rear feet are articulated at their upper ends on the seat framework, so that each can pivot about a horizontal and transverse pivot axle. The front anchorage comprises a joint having a traverse horizontal pivot axle, which allows the front foot to pivot forwards from its normal position about the joint pivot axle. The energy absorption device extends between the lower front anchorage and the upper part of the rear foot, but at a distance from the upper rear joint. The energy absorption device includes a stop mechanism for preventing the forward pivoting of the rear foot about its lower rear anchorage on the fixed structure of the craft.