Proven benefits in treating equine
musculoskeletal pain with Hofmag
A dissertation research project
by Andrea Good, BSc (Hons) Vet Phys
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Establishing the effects of
high intensity PEMF, Hofmag,
on the musculoskeletal pain
in horses
Proven benefits in treating equine
musculoskeletal pain with Hofmag
A dissertation research project by
Andrea Good, BSc (Hons) Vet Phys.
Andrea Good is a Veterinary Physiotherapist
and horse owner, based in the UK. With hands-
on experience of how injury, tight, stiff muscles,
decreased flexibility and range of motion can
affect horses, Andrea knows the importance,
both personally and professionally, of the
right treatment.
As part of her extensive studies, Andrea loaned
a high intensity PEMF machine from Hofmag
to use in a study to establish its effects on
musculoskeletal pain in horses. There was no
funding for this study by Hofmag and Andrea has
no affiliation with the company and can, therefore,
be considered independent. The only contribution
given by Hofmag was the advice to use the
machine during the study for 30 minutes a day,
for 5 consecutive days, in order to measure the
therapeutic effect in a short space of time.
The study was conducted as a blinded,
randomised control trial (RCT). RCTs are
considered the gold standard when attempting
to establish the efficacy of an applied intervention
with no selection bias and a robust, statistically
significant outcome.
The study was conducted
as a blinded, randomised
control trial, considered the
gold standard when attempting
to establish the efficacy of an
applied intervention
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22 horses were included in total. There were 9 in
the control group, and 13 in the treatment group.
The horses represented a broad range of ages
(4 to 25 years old), breeds and sex. Some were
field kept and some were part stabled. All were
in regular work defined as being active for 2 to 5
days each week. This is reflective of the typical
demographic seen in the veterinary physiotherapy
field. Throughout the trial, they were kept under
the same living and working conditions as their
normal lives before the study.
None were classified as lame but all were
experiencing some level of musculoskeletal pain.
However, they were all confirmed by their primary
care vet as having no major prior pathology and
none were on any medication. Owners were asked
to abstain from giving any other musculoskeletal
therapy throughout the duration of the study
unless directed by the primary care vet, in which
case, they would’ve been removed from the study.
The blinded assessor, who was qualified in equine
massage and rehabilitation, was not privy to
which horse was allocated to which treatment
group. On day zero they conducted four
assessments for each horse.
Following this, the horses in the treatment group
received the prescribed treatment of 30 minutes
daily for 5 consecutive days, while the control
group received no treatment. There was no set
protocol on what area of the horse was treated,
rather treatment was focussed on the areas each
particular horse needed help with.
On day 6, the same blinded assessor returned to
retake outcome measurements. To avoid bias, the
assessor was not privy to the outcome measures
and scores from day zero when conducting the
assessments on day 6.
The blinded assessor (who
was not privy to which horse
was allocated which treatment
group) conducted four
assessments for each horse.
Following this, the horses in
the treatment group received
the prescribed treatment
of 30 minutes daily for five
consecutive days
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The four
outcome measures
Four assessments were used to assess
outcomes on each horse on day zero,
and the same four were carried out
on day six – muscle palpation, limb
passive range of motion (PROM),
spinal PROM and mechanical
noiceceptive threshold (MNT).
In each assessment, the scores from each horse
were added up to give a whole horse calculation
for each individual.
Muscle palpation
The blinded assessor performed a detailed
muscular assessment on all superficial muscles
bilaterally and graded them on a scale of 0-5
according to tone.
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Spinal PROM
An assessment to measure restrictions in lateral
flexion at each specified vertebral landmark,
including C1 to C5 and T9 to T18, grading them
on a scale from 0 to 3.
MNT
A pressure algometer was applied to 10 soft tissue
and boney landmarks, bilaterally to determine
the minimum pressure required to induce a pain
behaviour or response.
This test is considered an objective or semi
objective assessment. While the three previous
assessments are subject to the professional
opinion of the assessor, MNT gives a quantifiable
force reading but is still subject to human
interpretation of behaviour. Tolerance to pressure
is typically lower when applied to a bruised or
injured area compared to a healthy area.
Limb PROM
An assessment to observe restrictions in limb
flexion, protraction, retraction and palpable soft
tissue restrictions in the scapular (shoulder),
grading them on a scale from 0 to 3.
Four assessments were used to
assess outcomes on each horse
on day zero, and the same four
were carried out on day 6, muscle
palpation, limb passive range of
motion (PROM), spinal PROM and
mechanical noiceceptive
threshold (MNT)
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Significant positive
results in the entire
treatment group
The only horses to improve in all
four assessment categories were
those in the treatment group.
Some horses from the control group did improve
in some areas but this improvement was generally
marginal by comparison and likely to be explained
by confounding variables. For example, being
ridden on day zero or day six, the assessment
days, wearing a poorly fitting saddle, or chance.
The improvements in the treatment group are
statistically significant and the team were able
to return an overall P value of P=<0.001.
01.
Number of Equines Showing Positive
Musculoskeletal Improvements
ASSESSMENT RESULTS
Muscle
Limb PROM
Spinal PROM
MNT
02
04
06
08
10
12
13
13
13
13
IMPROVEMENT
What is a P Value?
In scientific studies, the P value
is a measure of probability.
It’s the number used to describe
how likely it is that the changes
that have been observed would
have occurred by random chance.
A P value of less than 0.05 is
generally considered to be
clinically significant.
P=0.05 means 95% confidence.
The only horses to
improve in all four
assessment categories
were those in the
treatment group
C O N T R O L
T R E AT M E N T
TREATMENT / CONTROL
200
180
160
140
120
100
80
LIMB PROM GRADE
04.
TREATMENT / CONTROL
25
20
15
10
05
LIMB PROM GRADE
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The muscle palpation box plot shows that there was no significant
difference between the control group and the treatment group on day zero.
This confirms adequate randomisation within the study. For example, the worst
horses were not chosen for the treatment group. The line graph shows a significant
decrease in scores after treatment, indicating that muscle tone had improved.
The limb PROM and spinal PROM control groups demonstrate a marginal
increase in scores, indicating confounding variables or chance.
However, the treatment group in both demonstrated a decrease in scores,
by over half. Again, demonstrating a significantly positive response.
Digging deeper
into the results
Box Plot Showing the Distribution of Limb PROM Data
DAY 0
DAY 6
TREATMENT / CONTROL
MEAN
03.
Line Plot Comparing Muscle Data
BEFORE
TREATMENT / CONTROL
AFTER
120
115
110
105
100
95
90
MEAN
05.
Line Plot Comparing Limb PROM Data
DAY 0
DAY 6
20
18
16
14
12
10
08
06
04
C O N T R O L
T R E AT M E N T
C O N T R O L
T R E AT M E N T
02.
Box Plot Showing the Distribution of Muscle Data
DAY 0
DAY 6
TREATMENT / CONTROL
100
80
60
40
20
SPINAL PROM GRADE
08.
TREATMENT / CONTROL
1000
1200
1400
1600
800
600
400
MNT Value
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For the first three assessments a decrease in scores indicated a positive response.
In the case of the pressure algometer used to measure MNT, an increase in scores
indicated a positive outcome measurement.
Both the control group and the treatment group demonstrated an increase.
However, this increase is marginal in the control group compared to a significant
increase in the treatment group. Confounding variables and chance will
play a part in this.
There is an additional need to consider the
conditions in this assessment. Two horses
(Fifi and Clancy) in the control group were initially
assessed on day zero in cold, wet conditions
and then assessed again on day six in dry, sunny
conditions. Pressure algometry results can
be affected by ambient temperature. That is,
tolerance to a noxious stimuli will be lowered in
poor weather conditions, explaining this marginal
increase in scores in the control group.
07.
Line Plot Comparing the Spinal PROM Data
DAY 0
TREATMENT / CONTROL
DAY 6
65
60
55
50
45
40
35
30
MEAN
06.
Box Plot Showing the Distribution of Spinal PROM Data
DAY 0
DAY 6
Box Plot Showing MNT Value Data
DAY 0
DAY 6
TREATMENT / CONTROL
MEAN
09.
Line Graph Showing Te Mean MNT Values
DAY 0
DAY 6
950
900
850
800
750
700
650
600
550
C O N T R O L
T R E AT M E N T
C O N T R O L
T R E AT M E N T
CONTROL GROUP (ONLY)
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A P value of less than P=0.05 was returned for all four assessments.
In particular, the limb and spinal PROM assessments returned a P value of
less than P=<0.001. In other words, there is a less than a 0.1% chance that the
changes observed were down to anything other than the treatment by the
Hofmag device.
This means a clinically significant result in all four assessments.
Individual Statistical Results
Muscle Palpation
Limb PROM
Spinal PROM
MNT
P=0.003
P=<0.001
P=<0.001
P=0.032
01.
Before and after MNT Values
Before
After
200
400
600
800
1000
400.5
590.9
540.2
562.5
506.1
466.9
666.7
1009.8
673.5
507
538.3
55.01
656.3
822.8
582.5
676.4
435.5
366.7
MNT CALCULATION
H A R R Y
R O C K S TA R
P R I N C E T O O L E Y
B L U E
C P N N O R
F I F I
C L A N C Y
C O C O
G O L D I E
H A R R Y
R O C K S TA R
P R I N C E T O O L E Y
B L U E
C P N N O R
F I F I
C L A N C Y
C O C O
G O L D I E
H A R R Y
R O C K S TA R
P R I N C E T O O L E Y
B L U E
C P N N O R
F I F I
C L A N C Y
C O C O
G O L D I E
The improvements in
the treatment group are
statistically significant
and the team were able
to return an overall
P value of P=<0.001
10
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The findings support the previous
studies performed on humans that
found that PEMF had a positive
effect on muscle tone and pain.
For practitioners, this means
confidence in the use of high
intensity PEMF. An increase in
active range of motion (how much
the animal is choosing to move
their limbs and body of their own
accord) will naturally follow an
improvement in limb and spinal
passive range of motion.
Treating equine
musculoskeletal pain
with PEMF
In conclusion, it can be said,
scientifically, that the Hofmag
device has a significantly positive
effect on musculoskeletal pain
in horses in terms of muscle tone,
limb and spinal passive range
of movement and pain
modulation in horses.
In conclusion, it can be
said, scientifically, that
the Hofmag device has a
significantly positive effect
on musculoskeletal pain
in horses