A related rating is stiffness which tells how much pressure must be applied to the same thickness wood before it bends or breaks. This is the important rating that determines what kind of load can be placed on a beam or joist or any structural horizontal timber. This is also important to determining the size of a long column which may be subject to bowing under load. Crushing strength or hardness is the property that tells how easily the grain can be collapsed by heavy or concentrated pressures. This is important in determining a wood's fitness as a flooring or as a column which may be subject to large amounts of pressure.
Shock resistance tells how well a given species withstands momentary blows or changes in pressure.
Some woods, while capable of bending without fracturing, if done slowly, will break when forced into the same bend instantly. Good examples of where this characteristic is important is in wooden handles for hammers or the interior laminates of a bow or downhill skis. Movement tells how much a given species of wood will shrink or swell with changes in humidity. All wood expands when it increases its moisture content and contracts when its moisture content is reduced. As humidity changes throughout the year, so does the moisture content of wood.