Science in the Saddle: Peak performance or just pressure?

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Science in the Saddle:
Peak performance
or just pressure?
Equitation Scientists are studying the effects
and consequences of saddlery tradition
and innovation.
Rigid, sprung tree, or treeless? Moulded,
full panel or half panel? Flocked or air?
With so many options, how do our choices
affect our horses?
Lisa Ashton, Director of EquiSci, reports
from the 9th International Society for
Equitation Science (ISES) conference in
Delaware, USA where plenary speaker and
leading researcher in this field,
Dr Hilary Clayton, BVMS, PhD, Dipl.
ACVSMR, MRCVS explored the horse-ridersaddle interface.
In the beginning
Delegates quickly learned how far equitation science
has travelled. From the ‘bum prints’ left on putties that
mould to pressure, to students with a talent for running
(before wireless was invented, pressure pads had to
remain physically connected to a computer), Dr Clayton
explained the importance that technology development
has already had in improving horse welfare.
Equitation scientists are encouraging engineers to come
up with new ways to measure the pressure riders and
their equipment exert on horses. Pressure mats, wireless
devices and smart textiles to record force values,
distributions and thresholds are gradually improving in
the bid to tackle the complexity of the horse-rider-saddle
interface.
Multifactorial and complex
Saddle blankets with built-in sensors that measure the
dynamic pressure distribution between the saddle and
the horse are commercially available to researchers and
saddle manufacturers alike.
This technology, however, is complex to use. These
pressure mats contain 256 sensors that record 15,000
measurements per second! “The greatest challenge for
scientists” explained Dr Clayton, “is knowing how to
analyse the information. What is the most important
variable? The horse, rider or saddle?” asked Dr Clayton.
Page 48 • HORSES and PEOPLE • Phone: 07 5467 9796 • [email protected]
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SCIENCE CORNER
Big and flashy
Photo by Elke Hartmann, courtesy of ISES
How a horse is ‘put together’ and how
he or she moves, directly influences peak
pressures. The shape of the horse’s back
affects the pressures that are exerted
vertically. Movement and, in particular,
the amount of suspension in your horse’s
trot and canter also plays a role. The
greater the suspension phase, the higher
the maximum forces, and with it, the
potential for injury.
The faster the gait, the greater
the pressure
Minimum and maximum pressures are
the most important when assessing the
effect of the rider. Dr Clayton explained,
“Maximum pressures in the walk are the
same as the rider’s body weight, whilst in
trot they are twice the rider’s body weight,
and in canter up to three times the rider’s
body weight.”
Clayton’s research has shown the walk
creates the smallest range of pressures
and this minimum variation is due to the
walk having no suspension phase. In trot,
the highest pressures - twice the rider’s
weight - correspond to the moments when
the horse is in the diagonal stance phase
(when each diagonal pair of hooves are
on the ground). The greatest pressures
(three times the rider’s body weight), occur
during the stance phase in the canter. oth
the minimum and maximum pressures are
higher in each canter stride than they are
in walk or trot.
“
With 256 sensors taking 15,000
measurements per second, the greatest
challenge for scientists measuring saddle
pressures is knowing how to analyse the
information.
What is the most important variable?
The horse, the rider or the saddle?
The revival of rising trot?
Not surprisingly the downward forces
are higher in sitting trot, so it seems to
confirm that the more opportunities
you have to rise, the better for your
horse. Interestingly, the British
governing body for dressage recently
changed their rules so riders can now
compete up to medium level in rising
trot.
Image courtesy of Novel
The saddle area
How does the rider sit? How does the saddle fit? What does the horse feel?
Pliance®-s measures the dynamic pressure distribution between the saddle and the horse
using a thin elastic sensor mat. It is possible to assess quantitatively the rider’s signals
and the subsequent reaction of the horse. The technique of the rider can be objectively
assessed and corrected. Data can be immediately viewed with easy-to-use software.
Pliance®-s is marketed by Novel as the most advanced dynamic saddle-fitting monitor.
You can find out more on the website: www.novel.de
A pressure scan also shows the area
of force. A study from Vienna looked
at pressure distribution patterns,
identifying signature patterns for each
gait. When the scapula comes back
as the leg is protracted, the centre of
pressure under the saddle does not
move very far, compared with trot.
In trot, the loading pattern is front
to back and not always symmetrical
from left to right. Dr Clayton was
quick to point out this is not a defect
of rider or saddle.
As canter is an asymmetrical gait, the
loading pattern is not reversed on the
left and right leads.
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www.horsesandpeople.com.au • HORSES and PEOPLE • Page 49
and
Cristina Wilkins
“
The greatest saddle
pressures - three times
the rider’s weight occur during the stance
phase in the canter.
Both the minimum and
maximum pressures are
higher in each canter
stride than they are in
walk or trot.
Cushioning the rider
With so many different designs, materials
and types of saddles, can technology assist
your horse’s comfort, all of the time?
Image courtesy Dr Hilary Clayton
A saddle panel is a saddle panel, right?
Wrong! Scientists have analysed the shape
and slope of saddle panels, identifying
that flatter panels increase surface area,
thus reducing forces. If you only have
one saddle to fit many horses, Dr Clayton
recommended flatter panels will help to fit
a number of different backs.
The pressure sensing saddle pads send data to a computer.
The specially-developed software gives users optional views of the pressures.
Delegates were also interested in the
materials inside a panel, in particular the
number of different air systems on the
market. Dr Clayton clarified for delegates
that air panels are complex to get right,
and that, when over-inflated, air panels
are very hard.
Saddle fitting problems
How the horse moves
Swing Phase: When the hoof is
not in contact with the ground
Protract: The leg swings forwards
Using technology to record total forces,
any slight loading of pressure, for example
in the middle of your saddle, is easily
detected by a saddle fitter. Interestingly, in
a study that looked at one brand of treeless
saddle, all the loading occured in a small
area in the middle of the saddle.
Cristina Wilkins
Asymmetry: Is it the rider,
the saddle or the horse?
Stance Phase: When the hoof is
in contact with the ground
Retract: The leg swings backwards
Dr Clayton also warned delegates not to
assume an asymmetric saddle scan means
the saddle does not fit. At last year’s ISES
Conference in Edinburgh, Dr Sue Dyson
from the UK’s Animal Health Trust spoke
about the relationship between saddle
slip and hindlimb lameness. Dr Dyson’s
findings suggest that hindlimb lameness is
one of the most common causes of lateral
saddle slippage.
Page 50 • HORSES and PEOPLE • Phone: 07 5467 9796 • [email protected]
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SCIENCE CORNER
How much pressure is damaging?
Localised pressure can cause sores
or ulcers, whilst friction can cause
problems when your horse’s skin is hot
and sweaty. Scientists know pressure in
blood capillaries is 4.3 kPa. Any higher
can potentially cause problems, but as
Dr Clayton explained, “Saddle pressure is
always increasing and decreasing loading,
so potentially it is less damaging than a
constant continuous load.”
In one study, scientists recorded mean and
maximum saddle pressures in walk, trot
and canter of three groups of horses.
The first group showed dry spots when
the saddle is removed, something which
is indicative of high pressure cutting off
blood supply to sweat glands.
The second group showed clinical signs
of saddle sores such as swelling, heat
and pain on palpation.
The third was used as a control. The
horses showed no back pain and carried
well-fitting saddles.
Unsurprisingly, the lowest values
recorded were in the control horses.
The highest pressures were recorded
on the horses with clinical signs of
injury and these were higher than in
the horses with dry spots.
The mean pressure during an entire
stride was greater than 11 kPA with
maximum pressures greater than 30
kPa, which is potentially indicative of
a problem.
As a result of this work, scientists are
working with these values to establish
threshold levels and improve horse
welfare globally.
continues next page...
Kirra Lemon
Cristina Wilkins
Magnitude and duration of pressure are
important. Saddle pressure is different to
any other pressure (rug/blanket pressure
is more continuous). Dr Clayton urged
scientists and saddle fitters to look at every
situation individually. Some tissues are
more sensitive than others, with muscles
being particularly sensitive.
Three recent studies have looked at the
relationship between saddle pressures and
signs of back pain/injury.
Dry spots occur when high pressures cut-off the blood supply to
sweat glands in the area.
Focal areas of high pressure under the saddle can create ulcers
and lead to tissue necrosis.
Why do you use a saddle pad?
In an Australian survey, scientists from the
University of Sydney asked over a thousand
riders why they used layers between the horse’s
back and the saddle (see graph).
Over eight hundred respondents said they use a
pad to increase their horse’s comfort.
The second most popular reason was ‘to soak up
the sweat the horse produces’. The third was ‘to
keep the saddle clean’ , and fourth, ‘because that
is the way I was taught’. Only 14 respondents
said they did not use a saddle pad.
The researchers remarked that even though
‘helping to balance the saddle’ represented 27%
of responses there is no evidence to suggest
that layers can address poor saddle fit issues in
the longer term.
The abstract for: A retrospective survey of riders’ opinions of the use of saddle pads in horses, Lesley A. Hawson, Andrew N. McLean and Paul D.
McGreevy is available online: http://www.journalvetbehavior.com/article/S1558-7878(12)00076-7/abstract
www.horsesandpeople.com.au • HORSES and PEOPLE • Page 51
Equitation Science international
What about girths?
The British Equestrian Federation World Class programme
decided to measure peak pressures under a girth to give
their Olympic team a competitive advantage. With so many
variables in girth use - position, shape, length and material is it possible to test ‘what’s in it for the horse?’
Understand the
science, application and
ethics of horse training
Online and residential courses
for owners, riders, coaches, trainers, parents and anyone
interested in horses and optimising horse training and welfare
Discover more at www.aebc.com.au
or phone (03) 5787 1374
GIDGEE EYES
See the difference
The UK study used a calibrated pressure mat placed under
elite horse girths to determine the location of peak pressures.
Although most people assume that the girth’s main pressure
would be on the sternum, the scientists found that peak
pressures were located over the musculature behind the point
of the elbow. As these muscles are responsible for locomotion
and maintenance of posture, the scientists hypothesised that
peak pressures or restrictions could potentially inhibit the
horse’s movement and stride length.
These findings inspired a new design of ‘anatomical’ girth to
lower peak pressure distribution. For the study, twenty elite
horses and riders (with no lameness or performance problems)
were ridden in the newly-designed (performance) girth and
their standard girth in a double-blinded cross-over design.
Scientists measured pressures in all gaits. Using high-speed
video gait analysis, they also captured forelimb and hindlimb
protraction as an indication of stride length, as well as knee
and hock flexion.
The standard girth recorded high maximum forces, 22% (left
side) and 14% (right side) greater than the performance girth,
and peak pressures were 76% (left side) and 98% (right side)
greater.
In addition, the performance girth measured a 6–11%
increased forelimb protraction, 10–20% greater hindlimb
protraction, 4% greater carpal flexion and 3% greater tarsal
flexion than the standard girth.
By reducing girth peak pressures, the study increased the
efficiency of the thoracic serratus ventralis and pectoral
muscles (active during forelimb protraction), resulting in greater
forelimb protraction. The girth design is marketed by Fairfax
saddles as the performance girth.
www.gidgee-eyes.com
The research is titled: A girth designed to avoid peak pressure
locations increases limb protraction and flexion during flight by
Murray R.1,*, Guire R.2, Fisher M.3, Fairfax V.4 The abstract is
available online: http://onlinelibrary.wiley.com/doi/10.1111/
evj.12145_19/abstract
Page 52 • HORSES and PEOPLE • Phone: 07 5467 9796 • [email protected]
Which saddle pad?
Does your saddle pad help lower
maximum forces and effectively spread
your force throughout the stride?
Scientists have studied maximum forces
under different saddle pads, evaluating
their ability to cushion forces.
Studies from Vienna demonstrated
reindeer fur as the best material in walk
and trot. In another study, different pads
were placed under saddles with trees that
were too wide to see if fit would improve.
Foam and gel pads lowered maximum
forces by 44% in the walk, whilst gel and
reindeer fur reduced forces by 61% in
trot, although there was significant interhorse variation.
Dr Clayton’s studies have also reported
sheepskin, a natural fibre, as the most
effective in spreading forces more
evenly. Dr Clayton warns, however, one
should not use a sheepskin saddle pad
to compensate for any ill-fitting saddle!
“Sheepskin saddle pads can be useful to
help a well-fitting saddle fit better on
different horses,” explained Dr Clayton.
“
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SCIENCE CORNER
I am inspired by evidence informing our
equestrian practice and confident that
equitation science will keep pushing
forwards, improving our practices and
enhancing our relationships, helping us
meet the needs of our horses.
ABOVE: Studies suggest that the right
choice of saddle pad can decrease
maximum forces and pressure distribution
A smart future
Several teams of researchers worldwide
are investigating smart textiles - materials
that enable digital components and
electronics to be built into the fabric - to
help them answer important equitation
science questions.
Did you know?
Saddles vs bareback riding
Dr Clayton has also researched
forces with a conventional saddle
and bareback. Maximum forces were
twice as high bareback, with a more
shearing force (sliding against horse
hair) recorded.
Rider movement
Scientists measuring riders’ range of
motion in the saddle identified small
movements in elite riders to more
lateral movements from riders with
cerebral palsy.
Sensors seamlessley buried in our horse’s
normal equipment, like the girth, the bit, the
noseband or the saddle, will measure these
pressures, and more, in the not too distant
future.
“As we continue in an era of rapid
technological growth, I am inspired by
evidence informing our equestrian practice
and confident that equitation science will
keep pushing forwards, improving our
practices and enhancing our relationships,
helping us meet the needs of our horses.”
Next month, we continue our report
from the 2013 International Equitation
Science Conference, which took place
in Delaware, USA, with what was a
very well-received plenary by Prof
Jan Ladewig from the Copenhagen
University, Denmark, who asked: ‘What
about the other 23 hours in the day?’
Prof Jan Ladewig is, like Dr Hilary
Clayton, an Honorary Fellow of the
International Society for Equitation
Science.
and
Does science have the scope to solve
age-old welfare problems? Swedish
student Johanna Ternström presented
a unique collaboration of horse-ridersaddle interactions between Chalmers
University, Gothenburg University, the
Swedish School of Textiles, the Australian
Equine Behavior Centre and the
University of Sydney.
Interesting reading links:
The effects of different saddle pads on forces and pressure distribution beneath a fitting
saddle, Kotschwar et al. Link: http://www.ncbi.nlm.nih.gov/pubmed/20156245
The influence of different saddle pads on force and pressure changes beneath saddles
with excessively wide trees, Kotschwar et al. Link: http://www.ncbi.nlm.nih.gov/
pubmed/19362030
Evaluation of pressure distribution under an English saddle at walk, trot and canter,
Fruehwirth et al. Link: http://www.ncbi.nlm.nih.gov/pubmed/15656510
Relationship between saddle pressure measurements and clinical signs of saddle
soreness at the withers, by von Peinen et al. Link: http://www.ncbi.nlm.nih.gov/
pubmed/21059075
Vertical forces on the horse’s back in sitting and rising trot, de Cocq et al. Link: http://
dare.ubvu.vu.nl/bitstream/handle/1871/40135/CocDunCla_2009.pdf?sequence=1
About the Author: Lisa Ashton, BA (Hons), PGCE, MBA, Cert ESI, BHS
II, Pony Club A’Test holds the Equitation Science International Certificate
and tutors students from around the world studying Equitation Science
International Qualifications, awarded by the Australian Equine Behaviour
Centre. In 2011, she developed EquiSci to help horses by educating
riders, trainers, coaches and veterinarians in understanding and correctly
applying the science of how horses learn and its impact on horse training.
Visit www.equitationscience.co.uk for more information.
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