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shoes with an 11 to 14 millimeter mid-
sole height difference from between
the top of the forefoot platform to
the top of the midsole’s
heel. The other com-
prised of forefoot
strikers running in
minimalist footwear
(minimalist shoe’s mid-
sole height varies from
dead flat or zero drop to 6
to 7 millimeter). For this study,
the researchers defined minimal-
ist midsole heights to range
from 0 to 4 millimeters.
The groups were divided
almost evenly. Ten rearfoot and nine
forefoot subjects used traditional gear
and 10 wore minimal product landing
on their forefoot. The study provided
all the participants with the appropriate
footwear to match the foot strike and
midsole category identified with
the runners. Then, all the run-
ners were asked to perform
specific running activities to
ensure the data would not
bias the recorded data. The
study did not take various
surfaces into account such as
pavement or non-paved, gender,
conditioning or fatigue effects of their sub-
jects and midsole design attributes (e.g.
shapes, densities, flexibility) that could
affect some of the measured forces.
The results were both predictable and
surprising. Rice, et al, figured the forefoot
strikers with the minimal kicks would
produce the lowest measured forces of
the three groups. That notion was born
out by their findings. What they did
not see coming was the combination
of forces on the groups running
in traditional running product
would be about the same. In
other words, the researchers
found almost no difference
between the forefoot strik-
ers and the rearfoot strikers
running in standard midsole
height trainers.
“Those who habitually
run in full minimal shoes had
lower vertical and resultant
loadrates than those who
habitually run in partial
minimal shoes. Additionally,
only those running in partial
minimal shoes exhibited
impact peaks in their vertical
ground reaction forces. This
further emphasizes the
importance of footwear,
and suggests that even
being habituated to a small
amount of cushioning can
lead to harder landings … The
results of this study suggest that
forefoot striking in shoes with the
least cushioning results in the low-
est rates of loading,” reports Rice, et al.
The researcher’s conclusions should
give pause to adherents of maximalist
footwear. Maximal footwear is available
in many different midsole drops but is
routinely offered in the same range as
tested in this study, or 0 to 4 millimeters.
Although maximalist footwear has
been around for more than five years,
it takes time before enough data is
collected to see the injury outcomes
associated with any type of footwear.
Also, the study’s scope did not take into
account, several important environmen-
tal factors such as training surfaces and
midsole design.
Midsoles continue to have major
attention paid to them in the pursuit of
the elusive perfect transition (a smooth
movement of the foot’s pressure path
while on the ground before take-off).
Although this study adds to sport medi-
cine’s literature, its ruminations suggest
more questions than it answered.
Source: U.S. Department of Labor & Commerce; Wells Fargo Securities
Source: OIA
So
O
Sou
20
60 64 68 72 76 80 84 88 92 96 00 04 08 12 16
21
22
23
20
21
22
23
20%
10%
0%
30%
40%
50%
60%
70%
6 11 16 21 26 31 36 41 46 51 56 61 66
10 15 20 25 30 35 40 45 50 55 60 66
Males
Females
Resultant ILR
Vertical ILR
Age
2015 Participation in Outdoor Activities, by Age
0
20
40
60
80
100
Percent of U.S. Adults 6+
(Peak IL R (BW.S.-1)
SRFS
SFFS
MFFS
partial
full
MFFS
20%
21.4% 20.7%
19.7% 20.4%
25%
Replacing employees is costly for
companies’bottom lines
y
80
70
60
50
40
30
The shoes used in the study. The minimalist
Inov-8 Bare-X-200 (top) and the traditional midsole
proportions of the Nike Air Pegasus 2006 (#18).
The full minimal shoe was not identified.
Comparative peak instantaneous loading rates (ILR) between the total loading
rate or resultant ILR experienced by the runners versus just the vertical
component of that force. Notice the MFFS Full or Minimal Forefoot strike
in full minimal footwear recorded the lowest impact forces. Standard shoe
(traditional) rearfoot strikers (SRFS) and standard shoe (traditional) forefoot
strikers (SFFS) had similar numbers in the forces measured.
Inside
Outdoor
|
Winter
2017
54