A seat restraint system whose torso belt includes an inflatable structure that inflates upon impact to protect the occupants of a vehicle such as an automobile. The inflatable structure is linked to a gas generator and crash sensor. When an impact above a predetermined level of severity is detected, the gas generator is ignited, inflating the inflatable structure which contracts in length as it inflates. In a preferred embodiment, the inflatable structure is a braided tube. As the braided tube inflates, the diameter of the tube increases significantly and its length decreases significantly, due to the orientation of the fibers comprising the braided tube. The contraction in length pretensions the seat belt system by pulling any slack out of the seat belt systems. In a frontal impact, the inflated structure restricts the forward motion of an occupant and distributes crash loads over a larger occupant surface area to reduce both primary and secondary injuries. In a side impact, the inflated structure passes over the occupant's shoulder, restricts occupant motion, distributes crash loads and provides head and neck protection.