This test is used to evaluate the durability of the sample to withstand vertical forces applied to the backrest over time. The test applies to backrests that are fixed or can be fixed as to retrain pivoting and have a backrest height less than 38 inches measured from the floor. The sample will be secured without inhibiting movement of the back or arms. A 16 inch loading device will be attached vertically to the backrest of each seating position of the sample. All seating positions will be tested separately. A vertical force of 200 lb. will be applied to each seating position for 10,000 cycles.