1. The effect of a novel lumbar orthosis on paraspinal muscle
activity: a pilot study
Charles W. Lindquist Jr. D.C. DACNB
Correspondence:
Frederick M. Graff, D.C. DABCO, Medical Director
Medolutions, LLC
Telephone: (614) 543.1743, ext 102
Email: fgraff@medolutions.com
ABSTRACT
Modifying the activity and improving the endurance of lumbar musculature during
dynamic and static activities is a key component of treatment for low back pain. This
paper presents a pilot study assessing the effect of a novel lumbar orthosis on lumbar
muscle activity. Nine asymptomatic volunteers (7 males and 2 females) ranging in age
from 22 to 55 years were recruited and six subjects were included in the final analysis.
The electromyographic (EMG) signals of the paraspinal muscles at the L4 vertebral level
were assessed while participants stood in a neutral position with or without the orthosis.
When wearing the orthosis, the electrical muscle activity was reduced by 51.3% (p=.03)
and 38.8% (p=.09) for longissimus and multifidus muscles, respectively. Collectively,
use of the orthosis reduced the activity of the paraspinal musculature by 46.2% (p<.05).
This pilot study suggests that this novel orthosis may provide external stability to the
spine and relieve muscle strain by reducing the recruitment of the paraspinal muscles.
Further well-controlled outcomes studies are needed to validate the effectiveness of this
orthosis in a large symptomatic patient population.
EMG muscle activity for longissimus and
signals to measure paraspinal muscle activity at the
multifidus with and without an orthosis.
L4 vertebral level, pre and post utilization of a novel Error bars represent one standard deviation.
Study Design: Used electromyographic (EMG)
lumbar orthosis.
70
Objective: The orthosis evaluated utilizes a unique
Summary of Background Data: There is
limited evidence of efficiency of lumbar supports
for treatment of low back pain.
Results: When wearing the lumbar orthosis, the
mean electrical muscle activity was reduced for the
paraspinal muscles by an average of 46.2% (95% CI
-5.6, 45.2).
Conclusion: This pilot study provides initial data
on the effectiveness of a novel lumbar orthosis at
reducing paraspinal muscle activity. The decreased
EMG activity may provide temporary symptomatic
relief to patients suffering from low back pain.
Key words: lumbar, orthosis, back pain, muscle
endurance, electromyographic signal.
60
Spikes/sec
and patented design and has been subjectively
demonstrated to help relieve pain.
Electromyography was utilized to determine the
effect of this orthosis on paraspinal musculature.
50
40
longissimus
30
multifidus
20
10
0
No Othosis
Orthosis
Conditions

2. The effect of a novel lumbar orthosis on paraspinal muscle
activity: a pilot study
Charles W. Lindquist Jr. D.C. DACNB
Study Design: Used electromyographic (EMG)
signals to measure paraspinal muscle activity at the
L4 vertebral level, pre and post utilization of a novel
lumbar orthosis.
Objective: The orthosis evaluated utilizes a unique
and patented design and has been subjectively
demonstrated to help relieve pain.
Electromyography was utilized to determine the
effect of this orthosis on paraspinal musculature.
Summary of Background Data: There is
limited evidence of efficiency of lumbar supports
for treatment of low back pain.
Results: When wearing the lumbar orthosis, the
mean electrical muscle activity was reduced for the
paraspinal muscles by an average of 46.2% (95% CI
-5.6, 45.2).
Conclusion: This pilot study provides initial data
on the effectiveness of a novel lumbar orthosis at
reducing paraspinal muscle activity. The decreased
EMG activity may provide temporary symptomatic
relief to patients suffering from low back pain.
Key words: lumbar, orthosis, back pain, muscle
endurance, electromyographic signal.
BACKGROUND
Low back pain is one of the most common
disorders and is a leading cause of disability in
the United States [1]. Non-operative
management of the disease is the preferable
treatment option, as surgical intervention is
more economically costly, may have
suboptimal long-term outcomes and may
require extended periods of reduced physical
activity during post-operative recovery [2].
Several non-operative treatments exist,
including physical therapy, pharmacological
interventions and bracing [2].
Lumbar orthoses are one of the most
commonly utilized braces for recurrent low
back pain. Despite the wide-spread use of over
the counter and custom made lumbar orthotics,
the effectiveness of these devices has been
debated and the method of action of lumbar
orthoses is largely unknown. Although chronic
low back pain is a multifactorial disease,
abnormal activity of the paraspinal musculature
has been implicated as a potential source of
lumbar pathologies. Increased activity of the
erector spinae muscles is a typical finding
among patients with low back pain [3].
Similarly, patients with a higher frequency
spectrum width during electromyographic
(EMG) analysis are at the highest risk for
developing low back pain in the future [4]. It is
suggested that this greater EMG signal and
higher muscle activity arises as a result of
structural or functional instability of the
vertebral structures [5]. To overcome this
instability, lumbo-sacral orthosis have been
developed to provide external support. These
lumbar braces have been theoretically and
experimentally tested and the efficacy of these
devices can be assessed through analysis of the
EMG signal [6]. With increasing external
support from the orthosis, there is a subsequent
decrease in muscle activity of the paraspinal
musculature [7].
Despite a large number of commercially
available lumbar orthoses, few have been
empirically evaluated for effectiveness using
EMG analysis. Patient-reported outcomes with
the use of low back braces offer important
insight into the efficacy of bracing, however
these reports are subjective, may be biased, and
do not offer information into the mechanism of
action of the pain relief. Additionally, many
confounding variables may also affect the
overall efficacy of lumbar orthotics. Previous
investigators have found that body mass index
(BMI) was negatively correlated with muscular
endurance, suggesting that patients with greater
BMI may have a greater response to a lumbar
orthosis that decreases muscle activity and
improves tolerance to static and dynamic
movements [8]. Therefore, the purpose of this
experimental pilot study was to evaluate the
effect of a novel lumbar orthosis on paraspinal
muscle activity. We hypothesized that this
orthosis would reduce the muscular activity of
the multifidus and longissimus during a static
standing task. We also hypothesized that
patients with a greater BMI would demonstrate
a larger reduction in EMG activity when
wearing the lumbar orthosis.

3. METHOD
Participants
Nine asymptomatic volunteers (7 males and 2 females) ranging in age from 22 to 55 years were
recruited from Southwest Chiropractic Clinic. Written informed consent was obtained from each
of the individuals prior to participating in any facet of the investigation. Of the nine volunteers,
six were included in the final analysis. One volunteer was excluded because reliable EMG signal
from the longissimus could not be obtained. Two volunteers were excluded due to a vasovagal
reflex during the EMG.
Apparatus
The redesigned orthosis (Bio-Back Lumbar Orthosis, Medolutions, LLC) used in this study
provided bilateral opposing forces on the lower back (lumbar) region posteriorly and the
abdominal region anteriorly (Figure 1). The posterior aspect of the orthosis was 5 inches tall to
provide adequate support to the lumbar region. The anterior panel was rounded to comfortably fit
an individual’s abdomen. The anterior front panel contained 3 slots on each side through which
the connective straps could be tightened to a comfortable fit. The posterior panel included a
lumbar dome to comfortably support the lower back region. The posterior lumbar panel also
contained three slots through which the posterior portion of the connective straps could be affixed
to the lumbar panel. Two connective straps were used to connect the anterior and posterior panels
and the length of this strap could be adjusted to accommodate differences in body sizes between
each individual. The straps were available in one of two sizes: the standard straps (27” for each
side) fit up to a 50” waist size, and the larger straps (40” for each side) were available for waist
sizes up to 78”. Each strap included a Velcro Hook Tab and a removable Velcro Hook Pad, which
allowed the strap to be inserted through the panel slots and then reconnected back to the panel.
The Hook Pad was removable in the case that the straps need to be cut and modified to a shorter
length.
Figure 1. The Bio-Back Lumbar Orthosis (Medolutions, LLC)
Front View
Hook Pad is between folded Loop
Strap
Smooth side of attached Hook Tab
Back View
Participants were instructed to apply the lumbar orthosis in a comfortable standing position. First,
the back panel with the Lumbar Dome was placed on their back. Then the front panel was
centered over their abdomen. Participants were asked to find the tip of the loose strap and then

4. thread the end through the innermost slot of the front panel and back through the outermost slot
(of the same panel) and temporarily reattach the strap to itself. Research staff examined each
individual and made sure both panels were centered, and then adjusted the tension of the belt to
16 pounds. Tension was monitored through the use of Spring scales attached to the ends of the
straps.
Experimental procedure
The muscle bellies of the longissimus and multifidus were identified by a licensed Chiropractic
Neurologist and a Nihon Kohden Neuropak 2 electrodiagnostic device was used to evaluate
muscle activity of these muscles. A 26 ga. Teflon coated monopolar electrode (needle) was
inserted just lateral to the spinous process of L4 and oriented towards the mid-lamina area. The
electrodes were placed within the longissimus and multifidus muscles through a ½ inch access
hole in the orthosis that was positioned 4.5 cm lateral of midline on the right side. The depth of
the longissimus needle insertion was 5 mm beyond first contact with the musculature. The needle
of the multifidus muscle was made to contact the mid-lamina region and was then withdrawn
approximately 3 mm. Appropriate sterilization procedures were employed during the application
of the EMG electrodes. The reference electrode was 3 cm from the site and appropriate grounding
was utilized. The muscular activity in these asymptomatic subjects was noted in the upright
standing position. Neutral upright posture was standardized between all subjects. A plumb line
fixed from the ceiling was made to pass through a line parallel with the external auditory meatus,
the glenohumeral joint, slightly posterior to the hip joint, and slightly anterior to the lateral
malleolus of the ankle. Muscular activity was measured in the neutral standing posture without
any tension on the orthotic straps. The straps on the orthosis were then pulled to 16 pounds
tension and the EMG signal was re-acquired. The frequency (spike/second) of the EMG signal
was calculated for each of the trials. Only EMG waveforms (spikes) over 50 uV were counted
towards the total frequency.
Statistical Analysis
Paired sample Wilcoxon signed rank test was used to compare the means and 95% confidence
intervals (CI) of the EMG signal between the two conditions (with or without wearing an
orthosis). Because of the variable nature of EMG and the preliminary nature of this study, a priori
alpha level was set at p 0.10. All statistical analyses were performed using the SAS software,
version 9.12 (SAS Institute Inc., Cary, NC). Because of the small sample size of this preliminary
investigation, qualitative analysis was performed to determine if BMI was related to changes in
EMG before and after wearing the lumbar orthosis.
RESULTS
Demographic information and EMG signals from the longissimus and multifidus of the six
participants with and without wearing the orthosis are given in Table 1. Participants ranged in age
from 25 to 55, with a mean age of 43.3 (SD=4.3). Participants included 1 female and 5 males.
BMI ranged from 19.2 to 32.8, with one patient classified as normal weight (between 18.5 and 25
Kg/m2), four classified as overweight (between 25 and 29.9 Kg/m2), and one classified as obese
(over 30 Kg/m2).
Table 1. Demographic data and EMG signal of the electrical muscle activity for six participants.
Subject ID
1
2
3
4
5
6
Gender
F
M
M
M
M
M
Age
25
47
50
39
55
44
BMI
19.2
25.1
26.1
27.4
28.8
32.8
Longissimus (Spikes/sec)
No orthosis
Orthosis
27
13
75
45
62
12
82
13
48
37
39
28
Multifidus (Spikes/sec)
No Orthosis Orthosis
13
10
48
23
68
36
67
41
52
23
31
26

5. Table 2. The effect of the lumbar orthosis on electrical muscle activity (Spikes/sec).
No Orthosis
Orthosis
lumbar muscles
Mean
95%CI
Mean
95%CI
longissimus
55.5
(33.2, 77.8)
24.7
(9.8, 39.6)
multifidus
46.5
(24.1, 68.9)
26.5 (15.0, 38.0)
Muscle group*
51.0
(29.6, 72.4)
25.6 (17.5, 33.6)
* combine effect of both longissimus and multifidus.
Difference
Mean
95%CI
30.8
(7.6, 54.1)
20.0
(-1.8, 41.0)
25.4
(5.6, 45.2)
P-value
0.03
0.09
<.05
Spikes/sec
Table 2 and Figure 2 represent EMG activity pre and post-tightening of the lumbar orthosis. When
wearing the lumbar orthosis, the mean electrical muscle activity was reduced 51.3% and 38.8% for the
longissimus and multifidus, respectively (Figure 3). Mean muscle activity was 30.8 spikes/sec
(95% CI 7.6, 54.1) for the
Figure 2. EMG muscle activity for longissimus and multifidus
longissimus and 20.0 spikes/sec
with and without an orthosis. Error bars represent one
(95% CI -1.8, 41.0) for the
standard deviation.
multifidus after tightening the
straps and wearing the brace in the
70
standing position. When both of
60
the paraspinal muscles were
50
averaged, use of the orthosis
40
reduced the muscle activity by
longissimus
30
46.2% to a mean of 25.4 spikes/sec
multifidus
20
(95% CI -5.6, 45.2). The effect size
10
for this analysis was 1.64 which
can be categorized as a moderate
0
No Othosis
Orthosis
effect size.
Conditions
Qualitative analysis of the relationship between BMI and change in EMG signal did not reveal
any consistent trend. The greatest change in EMG signal for the longissimus and the multifidus
occurred in patients with mid-range BMIs. There was no obvious relationship between BMI and
percentage change or mean change in EMG activity.
Figure 3. Mean reduction in EMG while wearing the orthosis. Error bars represent
standard deviation.
60
Spikes/sec
50
40
30
30.8
20
20.0
25.4
10
0
longissimus
multifidus
Muscles
Musle group

6. DISCUSSION
This paper presents pilot work evaluating the effect of a novel lumbar orthosis on the paraspinal
muscle activity during a static standing task by analyzing the EMG signal from two muscles often
implicated in the pathogenesis of chronic low back pain. We hypothesized that 1) the use of the
orthosis would significantly reduce the muscle activity of both the longissimus and the multifidus
2) participants with a higher BMI would have greater reductions in the muscle activity of both the
longissimus and the multifidus.
All six participants had an observed reduction in the muscle activity for both the longissimus and
the multifidus while wearing the orthosis. Additionally, there was a clinically meaningful and
significant reduction in mean muscle activity for the longissimus and multifidus. This supports
our hypothesis that the orthosis would significantly reduce muscle activity of the paraspinal
muscles in asymptomatic individuals. One potential explanation for the decreased muscle
activity is a concomitant increase in lumbar stability provided by the lumbar orthosis. Patients
with low back pain demonstrate altered muscle recruitment strategies in muscles that contribute
to trunk support [5]. This pilot study suggests that this novel orthosis may provide external
stability to the spine and relieve muscle strain by reducing the recruitment of the paraspinal
muscles. This is in agreement with previous studies that found when patients donned a lumbar
orthosis and performed a forward bending task, there was an increase in lumbar stability as
measured via fluoroscopy compared to the non-braced condition [9, 10]. Although some may
argue that decreased muscle activity may promote atrophy in the paraspinal muscles, a prior study
found that follow-up evaluations of individuals who wore lumbar orthoses for extended periods
of time did not demonstrate a decrease in isometric lumbar muscle strength. Perhaps more
importantly, other studies have found decreased pain and improved functional improvements after
long term use of lumbar orthosis [11-14].
When examining the effects of BMI on lumbar muscle activity, we found no obvious relationship
between BMI and EMG changes. Regardless of BMI, subjects demonstrated a reduction in EMG
activity. It is interesting to note that patients with mid-range BMI had a greater average and
percentage reduction in EMG activity, suggesting that overweight patients may have a greater
response to lumbar bracing than normal weight or obese individuals. Due to the small sample size,
we were not able to stratify participants to determine which anthropometric or demographic
variables influenced the response to the orthosis. Future research should be designed to evaluate
the effectiveness of this orthosis in a large symptomatic population to examine the effects of BMI,
age, and gender.
In conclusion, this pilot study provides proof of concept and initial data on the effectiveness of a
novel lumbar orthosis at reducing paraspinal muscle activity. The decreased EMG activity may
provide temporary symptomatic relief to patients suffering from low back pain. Use of this
device may play an important role in the comprehensive treatment plan of symptomatic patients.
Appropriate, proper lifting techniques and ergonomic strategies should be re-trained while
patients wear the lumbar orthosis. When using the device during retraining interventions,
participants may be able to relearn proper movement strategies that were not possible previously
because of lumbar pain or excessive and abnormal paraspinal activity. Future studies should be
conducted using this device to validate its effectiveness and method of action in a large group of
symptomatic individuals. These studies should utilize a large sample size to determine predictive
factors of positive response to the orthosis, which would aid in appropriate clinical utilization of
lumbar orthosis.

7. ACKNOWLEDGEMENTS:
I would like to acknowledge the contribution of ScienceDocs Inc. to this article
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