The Negative Heel Concept, originally conceived
by Anne Kalsø, a Danish-born health enthu-
siast, can be considered a form of rocker sole.
By lowering the heel strike area of the shoe,
the idea is to simulate walking on soft ground,
where the heel sinks in the earth or sand on
contact. With the foot at a slightly more dorsi-
flexed heel strike angle, the Achilles tendon is
stretched more than in a shoe with an elevated
heel. Many of the postural and health claims
made by the ‘rocker shoe’ devotees such as,
“Straighter Posture, Better Breathing, Tighter
thighs, Stronger Core muscles, and Leg and
Calf Toning” are also made by the companies
‘Earth’ and ‘Springboost,’ two companies that
still promote the negative heel concept without
a deliberate sole rocker. (Fig. 1)
The now well established modern rocker
sole trend started in 1996. Like Anne Kalsø’s
( Fig.2 )
negative heel concept (that became known as
‘Earth shoes’ in the 1970’s), Swiss engineer
Karl Műller discovered that walking barefoot in
the paddy fields of Korea changed his posture
Ad promoting the benefits of the "Negative Heel"
and relieved his back pain. Műller equated this
postural change to the semi-nomadic Masai
peoples of East Africa, well known for their ex-
cellent posture. Joint and back pain is mostly
unknown among these tribal people who enjoy
stable health and exhibit remarkable athletic
ability. After returning to Switzerland, Műller
realized that walking on modern hard surfaces
would require a different approach to
achieve the soft-landing heel strike
he experienced on softer ground.
Hence, the introduction of ultra
soft wedge in the heel of the
shoe – he credited his innova-
tion to the famous African tribe
and named it the Masai sensor.
(Fig. 2) The name MBT is a
simple acronym for Masai Barefoot
Technology. Inserting a deliberately
collapsing heel into the shoe automati-
cally resulted in two biomechanical changes.
1) It allowed the foot to achieve more dorsi-
flexion in the sagittal plane with a softer heel
strike and 2) it created a midsole rocker in the
middle of the shoe resulting in an active rolling
Current Pedorthics | May/June 2018
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