what-when-how
In Depth Tutorials and Information
Heel height
Wearing a heel rather than a lat sole will tend to shift load from under
the heel towards the forefoot, with a clear relationship to increased fore-
foot pressures. However, these may be of concern only when heel height
becomes significant and only when the forefoot area is not appropriately
protected.
A small heel may be advantageous because most people have worn
a heeled shoe all their lives and removing the heel may increase stress
on the Achilles tendon and posterior musculature. Since the effect of a
heel is to slightly plantarflex the foot relative to the leg, as the peak of
dorsiflexion occurs in late stance, less dorsiflexion will be needed to
advance the body's centre of mass over the foot. Reduced dorsiflexion
will reduce the stress experienced in the Achilles tendon.
A change in Achilles stress has been linked to altered calf muscle
activity and, since gastrocnemius crosses the knee, altered knee and
even hip function; however, there is little tangible evidence of effects of
small heels influencing joints quite so proximal.
A small heel of approximately 4 cm (depending on shoe size) is there-
fore beneficial. Additional height should be used only where there is a
clear difference in limb length. While much is made of the importance of
symmetrical gait and limb length, human anatomy is rarely symmetrical
and small (<1 cm) differences may be generally ignored. Measuring for
limb differences is very subjective and identifying that one limb is longer
than another is probably accurate only if the difference is 5 mm or more.
Less than this and soft tissue compression and the position of the patient
can quickly provide false positive results. It is often advised that multiple
measurements be carried out over a series of visits in order to take into
account variations in measurements and the process of measuring.
Controlling foot motion with footwear
As the foot hits the ground it will evert, the medial arch will lower and the
midfoot dorsiflex as load is borne under the forefoot. The design, con-
struction and choice of materials will influence the extent to which the
shoe resists this movement. This could be an advantageous function, in
order to reduce foot pronation for example, which may assist in resolving
foot and lower limb symptoms, but it may also cause problems, such as
blisters and sites of high pressure. The role of orthoses to control foot
motion has already been covered, so here the focus is footwear.
In combination with the heel collar height and throat of the shoe, the
contact area between the shoe upper and the dorsum of the foot, the
