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This a subject that has come from another thread as a “by line” discussion, l bring the topic to its own thread due to some interest and so that we do not detract from the original threads topic.
Two statements were made by two different posters about “straight lasts”
”In fact this is a urban myth.. there is no such thing as straight or curved last footwear.”
The other statement regarding straight/curved lasts..
“An urban myth???.....probably a podiatric myth, a running magazine myth and running shoe store myth also!!”
My problem comes from this has been made as General statement which is not based on fact.
Whilst some truth may lay deep in the marketing of “some” brands that have only modified the sole to help sell their product and they may have been made on the same last as the standard, this is not a factual statement about all manufactured shoes and their lasts.
When we and other shoe makers make a straight lasted shoe as a posed to a curved lasted shoe the upper is quite different, not always seen by the untrained eye, in fact the designer/pattern maker has gone to a great length of effort to hide the fact that it is different.
For example the inside/Medial quarters need to be shorter on a straight last than a curved last as there is less distance to cover over a straight line than a curved, if this is not done the lugs will appear crooked or the counter will be off the mid line, nether been exceptable. ..sadly the last is also heavier as there is more volume, very noticeable when working on a size 18UK shoe.
The opposite is true of a curved last product, the greater that medial curve is the longer the medial quarters need to be, extra allowance will also be needed at the medial aspect of the vamp pattern as most curved lasts extend that line through to the distal hallux to accommodate a Pes Cavus “type” foot where the hallux is abducting form the foot, again, none of this should be very visible if the “pattern maker” has done his/her job well.
The sole can reflect these differences, accentuate or it can hide these differences to a lesser degree, say a curved last, we can hide how deep that curve comes in by a slight flare of the midial mid foot of the sole.
There is one thing that "motion control" shoes are good for:
Usually these type of shoes are built in straighter lasts allowing a roomier fit for low arched wide type of feet, This roomier fit is only possible with straight lasted shoes.
If for nothing else these shoes are the best (if you consider fit alone) for wider low arched feet that are virtually impossible to properly fit in the curved lasts of neutral shoes.
We probably should address the concept of straight vs curved last footwear.
In fact this is a urban myth.. there is no such thing as straight or curved last footwear. Every company has maybe 3-4 major lasts they use, which relate more to volume than anything else.
The shoe is made to look "straight, by adding bulk to the medial midfoot, and it is made to look "curved" by heavily sculpting in this region.
Often a straight and curved shoe come off exactly the same actual last (plastic model the shoe is "lasted" from), and so the appearance is actually only visual, with very little functional difference.
The actual volume of the upper, and the width of the midsole/outsole combo are what influence fit. Curved/semi-curve/straight lasted shoes have no effect on performance, as is often quoted.
It is important to note that some companies spruik the merits of width fittings, but do so only by blowing out the volume of the upper,without increasing the base-net of the midsole/outsole. This will have very little fit benefit, as the wider foot just splays out over the midsole.
Thank you, thank you, thank you! I've been saying the same thing about "curved last vs straight last" shoes for years, but has anyone been listening??....no!! Most podiatrists and nearly all shoe sales personnel look at the bottom of the shoe sole and see a curve and think this means that the shoe is "curve-lasted" and then look at another shoe with a straighter medial sole border and say the shoe is "straight-lasted". Wrong!!
The last is the three-dimensional model about which the upper of the shoe is constructed, and has almost nothing to do with the shape of the shoe sole when viewed from plantarly. In running shoes, such as "motion-control" shoes, these shoe soles typically have a straight medial border in order to place more material under the medial arch of the shoe, which makes them heavier and more "clunky" to run in, but also makes them better at applying external supination moments to the foot. These shoes are often called "straight last shoes". A racing flat, on the other hand, may have very little medial arch sole/midsole which will not only make it lighter, but will also make it less able to exert external supination moments on the foot during running. These shoes are often called 'curved last shoes". Both of these shoes may be made over the same three-dimensional foot model (i.e. last) but may have very different abilities to exert supination forces on the foot due to their huge differences in midsole construction.
An urban myth???.....probably a podiatric myth, a running magazine myth and running shoe store myth also!!
Paulo then posted (I have cut and pasted his formatted message):
toomoon The shoe is made to look "straight, by adding bulk to the medial midfoot, and it is made to look "curved" by heavily sculpting in this region.
Even so the volume available in the shoe upper its completely different in both shoes.
toomoon It is important to note that some companies spruik the merits of width fittings, but do so only by blowing out the volume of the upper,without increasing the base-net of the midsole/outsole. This will have very little fit benefit, as the wider foot just splays out over the midsole.
Completely true in some but not in all models.
Kevin Kirby An urban myth???.....probably a podiatric myth, a running magazine myth and running shoe store myth also!!
Myth or no these shoes will not fit the same way:
(Please compare the volume available in the medial versus lateral side of each model)
Each shoe will have different fit and feel, alowing more or less volume and that's all I'm saying:, its easier to fit a low arched foot in a straight last, this is a problem I had to solve almost every day (shoe/foot Marriage)since 1993 in my professional life.
Comparing the transverse plane profile of shoe soles does not directly determine the fit of the upper on a foot. The fit of the upper is more determined by the three-dimensional shape of the last of the shoe, not the transverse plane profile of the shoe sole.
I also worked as a shoe fitter for a few summers, lectured at the California College of Podiatric Medicine for about five years on shoe history, shoe biomechanics and shoe-orthosis interactions, and have been a long distance runner and interested in running shoe technology for over 35 years. Simon is right: saying that the shoes you display in your photo are curved-lasted vs straight-lasted is improper terminology, but is commonly-used terminology, as I noted in my last posting.
In order to determine whether a shoe is made around a curved foot model or a straight foot model, one needs to determine the shape of the upper of the shoe, which is the part of the running shoe that is made to fit the last. Looking at the sole of the shoe from the plantar aspect only determines the transverse plane dimensions of the shoe sole, not the shape of the upper.