1. Stability vs Cushioning
Introduction
‘Well-known international athletes have successfully competed barefoot, most
notably Zola Budd-Pieterse from South Africa and the late Abebe Bikila from
Ethiopia.’ (Warburton 2001). Running barefoot is seen at the highest levels of
competition in running, which shows there is no hurdle to overcome the need for
achieving the highest levels. ‘The current trend is that many runners are moving back
to barefoot running or running in “minimal” shoes’. (Lohman et al 2011) Certain
athletes are choosing to save energy and decrease their likely hood of injury in favour
of far greater comfort that running trainers can provide. ‘It is claimed that footwear
increases the risk of such sprains, either by decreasing awareness of foot position
provided by feedback from plantar cutaneous’ (Warburton 2001). The current
argument over running shoes is that they hinder optimal performance in terms of them
slowing down the athlete’s performance when they land and take off. Obviously there
are no mixtures of footwear for stability and cushioning around so there has to be a
choice between the two. The advantages to wearing running shoes is obviously
greater protection of the feet in terms of preventing the ground from causing damage
such as materials found on the floor whether it is in the suburban/urban streets, or off
road. ‘Cushioning consists of highly resilient materials of relatively low hardness
(soft) used as an interface between foot and support surface, mainly in shoe midsoles.’
(Robbin et al 1998). The advantages to barefoot running is as explained earlier, less
time between landing and take off phase which means for quicker strides. Also
because there is less material surrounding the foot, there is less chance of injury, the
most common being sprained ankle. ‘Barefoot running is characterized by a
significantly larger loading rate than in shod running and, in general, more than one
impact peak was found for the barefoot condition’ (Wit et al 1999). Because there is a
significant difference between the two types, it is less of a surprise to learn that there
is a difference in running styles. ‘In barefoot running, placement of the foot is
significantly more horizontal than in the shod condition’ (Wit et al 1999). The greater
horizontal running style might be due to the fact there is less weight without running
trainers on the feet, which is also able to give a more stable foot strike. The aim of the
current study is to show the differences between in the five parameters which are F-
max, Fy, midstance timing, loading rate, maximum and minimum rear foot angle and
ROM (range of motion). The three types of footwear which were used in the
investigation were barefoot, fashion trainers which are Primark plimsolls’ and running
trainers which are New Balance 1080. The aim is to use the results from all three
types of footwear and come to a conclusion whether greater stability is worth taking
over cushioning when running for simple pleasure/health, to low/high level of
competition.

2. Use and review of lab tests
Six male participants from UCLAN University were tested while running under three
conditions, barefoot, fashion and running trainers, and were instructed to run between
3.8-4.2 ms. All participants did not have any current injuries that prevented them from
producing accurate results. The participant’s ages were 23 ± 3 years: weight 73.5kg ±
10.35kg. The fashion and running trainers were size 9, so all six participants were
between sizes 8-9 if not they weren’t able to record accurate enough results. The six
parameters used were measured using the Kistler force platform (record applied
forces of 10-10000N to an accuracy of ± 2%) which is placed in the centre of the 3D
cameras. The force plate itself is 600 by 400mm and has a depth of 45mm; it was four
piezo-electric crystals, one of each corner which can record force, torque, strain and
various others. The participant’s were also marked up on their right foot using four
reflective markers. They were placed on the calf, Achilles insertion, Achilles and heel.
This is because the 3D camera analysis was used in the experiment which recorded
the participant’s movement. This meant we were able to provide detailed images of
how the right leg moved without the need for high speed cameras which can only
record in 2D. Each participant was given time to warm up for each of the three
conditions to become familiar with the different amount of cushioning. This was done
while the investigators calibrated the 3D cameras; this was done after every
participant as they have to be recalibrated once every 30 minutes. The runners were
instructed to run using their normal technique whilst maintain a speed of between 3.8-
4.2 ms and hitting the force platform. The speed was calculated using the 3D cameras
from the marker placed on the xiphoid (between the breast plates), and also the
placement of the right foot was visually checked by the investigators as it was a
critical part of the experiment. All participants were required to run until three good
trails on each condition were recorded.
Figure 1 shows the eight 3D cameras (black circles) surrounding the force platform
(yellow rectangle). The red arrows show the direction of where the participants where
travelling which was from right to left of the biomechanics laboratory.

3. From the collection of data the step from heel to toe off was recorded using the 3D
cameras and the force platform for the five parameters. Two of the three orthogonal
components of the ground reaction forces were measured (Fz+Fy). Fx was not
recorded as it did not have significant relevance because that orthogonal component
looked at medial-lateral movement where the main focus was on anteria-prosteria and
vertical.
Fig. 2. Placement of the markers in the sagittal (A) (up to the calf) and frontal plane
(B) with the calculated angles.
In the experiment we used barefoot running, so with no material
(footwear) protecting the feet. Running in padded shoes would
have altered the running pattern and affected our overall results.
The Plimsoll is a shoe usually made out of black or white
coloured canvas. Normally they have a piece of thick elastic that
goes over the top of the foot to keep it on securely. The sole of
the shoe was made out of rubber.
(http://www.childofthe1980s.com/2008/04/28/black-plimsolls/)
New Balance 1080.
Our premium neutral-cushioning trainer that offers the ultimate
cushioned ride from heel to toe off, with N-Ergy and
ABZORB® FL midsole technology cushioning in the heel to
provide NB's most advanced shock absorption and cushioning
system. (http://www.newbalance.co.uk/Product/WR1080LS)
MediaLatera

4. Figure 5 shows participant 3 performing a barefoot trial at 4 m s. The vertical (Fz-blue line) rises
very steeply at impact peak, but its time from heel to midfoot is very short. There is a slight
increase in force before F-max, and there is also a very smooth propulsive phase indicating the
participant had a stable foot strike.
Figure 6 shows participant 3 performing a fashion trainer trial at 4 m s. The vertical (Fz-blue
line) once again shows a steep impact. However its transition from heel to midfoot is longer.
Again like the barefoot trial there is a brief increase in force before F-max, but the propulsive
phase is not as smooth indicating less stability at the end of the foot strike.
Figure 7 shows participant 3 performing a running trainer trial 4 m s. The vertical (Fz-blue line)
shows a less step impact peak. Its move from heel to midfoot is completed much quicker than the
other two conditions. There is no minor increase in force before F-max, and the propulsive phase
is far more unstable, starting from far more horizontally before steeply losing force.
Consideration of ergonomic issues

5. Final justified recommendations and conclusion
From the results gathered in this investigation, it showed that the fashion trainer
produced the largest amount of force with five of the six participants. The barefoot
running which possessed no material for cushioning was marginally off with three of
the six participants’ and with one actually producing more force than the fashion
trainer. With the running trainer (New Balance 1080) producing far less force with
every participant compared to the condition that produced the largest, not surprising
due to the N-Ergy and ABZORB® FL midsole technology cushioning in the heel. In a
study conducted by Clark et al (1983) who wanted to find the effects of shoe
cushioning upon ground reaction forces in running. ‘To determine the effects of
widely varying amounts of cushioning upon vertical force (VF) parameters, ten male
subjects, (mean weight = 68.0 kg) ran at a speed of 4.5 m . s-1 (6 min/mile pace) and
contacted a Kistler force platform. Two shoes were tested: a hard one and a softer
shoe that had 50% more cushioning as measured by an instrumented impact tester.
Each subject during which the ground reaction forces were sampled at 500 HZ using a
PDP 11/34 minicomputer. It was found that the time to the vertical force impact peak
was significantly longer in the soft shoe; however, no differences were seen in the
magnitudes’. Even though Clark et al (1983) didn’t find differences in force for
loading rate, they found that the soft shoe took longer to get impact peak due to its
50% extra cushioning, meaning the material was able to absorb the forces exerted
onto the softer shoes. Again this is unsurprising due to other studies on this particular
issue. ‘Barefoot running is characterized by a significantly larger loading rate than in
shod running and, in general, more than one impact peak was found for the barefoot
condition. In barefoot running, a significantly larger loading rate during impact (G;*)
was found, agreeing with results of previous studies. In barefoot running, placement
of the foot is significantly more horizontal than in the shod condition: the absolute
difference for the sole angle between the two conditions is 143 at 4.5 m s~1’. (Clercq
et al) The study conducted by Clercq et al found like the current study that barefoot
produced significantly larger loading rate than the softer conditions, which agreed
with previous studies before theirs. So what can be concluded from these two
previous studies and the one conducted recently is that the running trainer is far better
for cushioning than barefoot and in our study even better than the lack of cushioning
from the fashion trainer. However, while the running trainer proved it was the best for
cushioning, it also proved to be by far the least stable compared to the other two
conditions, apart from participants 2 and 6. As the running trainer is the least stable, it
carries the greatest risk of causing injury to athletes compared to the other two
conditions, the condition that proved to be the most stable was barefoot. This again is
unsurprising due to the lack of material the feet had to run with. Not only does
barefoot produce a more stable foot strike, it saves the athlete energy as they are
running. ‘Not surprisingly, materials used for cushioning in shoes absorb energy, and
stiff midsoles should produce a 2% saving of energy compared with standard
midsoles’ (Warburton 2001). The conclusion that can be drawn up from this current
study is that cushioning is to be a greater priority than stability. The reason for this is
because there is such a large difference in loading rate between both barefoot and the
fashion trainer compared to the running trainer. Even though the running trainer
produces the greatest range of motion out of the three conditions, in the opinion

6. gathered from the study, the damage caused by the force from less cushioned barefoot
and fashion trainer condition is not worth a more stable foot strike, as the feet are
more likely to suffer from the harder foot strikes, than a potential for injury from the
running trainer.
Self-reflection and learning
From personal experience I have found out that there is a significant difference
between the softer running trainer compared to the harder fashion trainer and barefoot
in loading rate and range of motion among the other parameters. However I don’t
think the issue was as well analysed as it could have been. The testing itself could
have been improved by putting more participants in, and comparing the five
parameters with participants of different shoe sizes to see if there is a difference in
cushioning and stability with participants of a higher or lower shoe size. This means
we could have had more data to analyse which would have made our findings more
superior. Also the way in which the data was analysed could have been improved,
each participant’s data was analysed by a different person, and this meant that there
would be difference in opinions on how certain parameters like the loading rate would
be written down, affecting results. Finally we could have added more parameters to
illustrate the importance of both stability and cushioning have on athletes, and to give
a clearer conclusion on which is better for runners. Overall I have learnt that the type
of running trainer is important to a runner as it is a vital component, however I have
also learnt that there are other options which can be considered which can improve on
a more stable foot strike and reduce energy lost in running. Even though I don’t think
the cost of cushioning is more important than stability, I think that runners and
athletes can use the barefoot option in order to achieve better results.

7. References
Clark. T.E., Frederick. E.C., and Cooper. L.B. (1983) Effects of shoe cushioning upon
ground reaction forces in running. International Journal of Sports Medicine. 4, p 247-
251.
Clercq D.D., and Wit B.D. Timing of the lower extremity motions during barefoot
and shod running at three different velocities. Movement and sport sciences,
University Gent, Belgium.
Nigg B.M. (2001). The Role of Impact Forces and Foot Pronation: A New Paradigm.
Clinical Journal of Sport Medicine, 11. 2–9.
Lohman EB 3rd, Balan Sackiriyas KS, Swen RW. (2011). A comparison of the
spatiotemporal parameters, kinematics, and biomechanics between shod, unshod, and
minimally supported running as compared to walking. Department of Physical
Therapy, School of Allied Health Professions, 12,4, 151-163.
Robbin S,. Waked. E,. and Saad. G. (1998). Do soft soles improve running shoes? 1-
4.
Warburton. W. (2001). Barefoot Running. Sport science. 5, 1-4.
Wit B.D., Clercq D.D., and Aerts P. (1999). Biomechanical analysis of the stance
phase during barefoot and shod running. Journal of Biomechanics. 33, 269-278.
http://www.childofthe1980s.com/2008/04/28/black-plimsolls/
http://www.newbalance.co.uk/Product/WR1080LS