A last is a block or form shaped like a person’s foot on which footwear is made. One of the secrets to creating a well-fitting hiking boot is the manufacturer’s choice of last. The manufacturer tries to choose a last that will accommodate the greatest number of people. Many companies devote considerable effort to studying and measuring feet, and to collecting a range of data. These efforts usually generate very positive results, in some cases producing lasts that correspond to the feet of 80% of the population.
Manufacturers can use different lasts for different types of footwear. A running shoe is not designed to fit the same way as a hiking boot. In the case of hiking boots, almost all manufacturers use the same approach. Lasts are designed to offer maximum toe space, more than the average for other types of footwear. This is because, on descent with a heavy backpack, a hiker’s foot tends to slide forward. Moreover, manufacturers generally choose a narrower heel to stabilize the foot and ensure that the boot flexes with the foot. Finally, the boot must be tight around the instep in order to keep the foot from sliding forward and to increase the boot’s lateral stability.
Once the last is chosen, the boot is built around it. First, the upper and the quarters are moulded on the last and joined at the back by the heel seat. Then, the sole is attached. This exacting process dictates the type of construction, or upper and sole assembly. There are four types of construction: Norwegian welts, slip-lasted construction, board-lasted construction and combination-lasted construction.
This type of construction—also called the Goodyear welt—was the traditional method used to construct hiking boots prior to the introduction of glues and other adhesives. This type of construction is advantageous because it solidly binds the upper and the sole, making their separation impossible. Moreover, resoling is much easier with this type of construction than with glues. See the figure for details.
This type of construction is very durable, but also very stiff. The leather used is generally quite thick, making break-in difficult. Norwegian welts have become quite rare because it is less expensive to manufacture boots using a board-lasted construction.
With the advent of new high-performance glues, the board-lasted construction has become the standard for hiking boots. The principle is simple: the insole is attached to the lower surface of the last. The upper is then stretched over the last and its edges are folded over the insole (which is now sandwiched between the last and the edges of the upper). The upper is glued to the insole. In some cases, staples or nails are added for a sturdier construction. The midsole is then glued over top, followed by the outsole. The last is removed from the boot and the footbed is inserted. This type of construction is used for most hiking boots currently on the market.
This construction offers numerous advantages. It is quick, less expensive than Norwegian welts and relatively solid, since today’s glues are highly adhesive and very effective. This manufacturing technique is quite versatile, since it allows for the use of a wide range of midsoles and outsoles. It is also a lighter construction. Finally, this construction allows for easy break-in, providing greater comfort at the outset.
This construction is generally not used for hiking boots. It is a flexible construction that is more suited to running shoes or light-hiking footwear. In this type of construction, the upper is folded over and stitched to form a type of moccasin. Once the stitching has been completed, the last is inserted into the footwear. The various sole components are then glued to the upper and the last is removed.
This type of construction is not often used for rigid footwear. A slip-lasted construction is used for the front of the shoe, from the arch to the toes. The back is more rigid because, as with a board-lasted construction, the upper is stitched to the insole. This results in a relatively stable boot on the underside of the foot, but may be too flexible at the front.
