Hello all,

Let's talk about lasts. A last is the form that is used to make a shoe. In running shoes, last has two meanings. The first is the shape of the shoe and the other is construction technique.

Most companies use more than one shape for their shoes. In fact, many use different lasts for men's and women's shoes of the same model. A well known example is New Balance. They have a SL 1 and a SL 2 last. The SL1 has standard proportions (similar to many companies). The SL 2 has a wider, shorter, and deeper toe box. It is narrower in the heel and higher in the instep. You will see more women's shoes with SL 2 than men's. The proportions of the SL 2 is closer to the average woman's foot. So in this case the "last" includes the upper!

There are basically three last shapes used in running: curved, semi-curved and straight. The straighter the last, the more stable (for overpronation) the shoe will be. Ceteris paribus (all else being equal).

Curved lasts are not used very much in training shoes but are prevelant in race flats. A curved last can promote pronation and not many need help in that catagory, but allows for a fast movement through the gait. The foot type that would use this shape in a trainer are supinators and underpronators.

Semi-curved is by far the most common shape. It works with a lot of feet and stability devices. Other names you may see for a semi-curved are universal and semi-straight.

Straight lasts are the most stable. These shoes tend be shaped like bricks. The arch area of the midsole is filled in. They tend to be wide based shoes. This shape is best for severe over pronator.

THE CATCH! There are straight lasted cushion shoes and semi curved motion control shoes!

By the way, I will discuss the pronation/supination thing very soon on another post.

When constructing a shoe there are four basic lasts: slip, strobel, combination, and full board.

To make a slip lasted shoe you pull the material of the upper around the form (last) and stitch it. If you pull the insole out of a shoe and there is stitching going down the middle that is slip lasted. This makes for a comfortable fit, though it can be inconsistant from shoe to shoe. It is also more flexible (ceteris paribus).

A strobel last is a bit more stable, more consistent in fit and and holds orthtics better than a slip last. To strobel last a shoe you put a felt (or any of a number of different materials) "board" under the foot and stitch the upper to it. This is becoming the most prevelant way to make a shoe.

A combination last combines the forefoot flexiblity of a slip last but has a "board" from the mid foot to the heel. This makes the heel very rigid. This makes the shoe stable and allows orthotics to sit nicely. There are fewer and fewer combination lasted shoes now.

Full board lasts are not used very often in running (I can't think of any off hand). It tends to make the forefoot too stiff. Great for dress shoes but not for runners.

Whew!!! That turned out much longer than I expected and I left a lot out!

Hopefully, you are not more confused. We will be touching on the above many more times.

More to follow...