Toraiwa et al.: Trunk harness effect on stability on prone hip extension

Asian Journal of Physical Therapy
Effects of a Trunk Harness on Lumbopelvic Stability and Muscle
Activity during Prone Hip Extension Exercise
Taro Toraiwa1,2, Sirinda Jaotawiparta1, Misaki Suzuki1,3, Hironobu Kuruma1
1

Tokyo Metropolitan University, Japan
Adachi Keiyu Orthopedic, Japan
Seikei-kai Chiba Medical Center, Japan

2
3

Corresponding Author:
Taro Toraiwa
Tokyo Metropolitan University
7-2-10, Higashiogu, Arakawa-Ku, Tokyo, Japan, 116-0012+81-90-4858-3923
ultora3923@gmail.com

Abstract
Background: Therapeutic exercise is essential in patients with low back pain and lumbopelvic instability. Intra-abdominal pressure
is necessary for ideal dynamic stabilization patterns. However, accurate performance of such exercises is a challenge. A trunk harness
can help stabilize and alter muscular patterns. This study aimed to examine the effects of using a trunk harness on lumbopelvic
stability and muscle activity during prone hip extension in healthy individuals and patients with low back pain. Methods: Sixteen
patients with low back pain and 15 healthy individuals performed prone hip extension under control, Dynamic Neuromuscular
Stabilization(DNS)-maneuver, and DNS-maneuver + harness conditions. Lumbopelvic kinematic data, muscle onset time of thebilateral erector spinae, semitendinosus, gluteus maximus, low back pain severity, and difficulty performing prone hip extension were
evaluated. Repeated-measures two-way analysis of variance was performed for each measurement item. The significant level was
set at 5%. Results: The lumbar lordosis angle was significantly lower in the DNS-maneuver and DNS-maneuver + harness conditions.
The anterior pelvic tilt angle was significantly lower, and muscle onset of the gluteus maximus and contralateral erector spinae
occurred earlier in the DNS-maneuver + harness condition. The difficulty of performing prone hip extension was significantly lower inthe DNS-maneuver and DNS-maneuver + harness conditions and was considerably lower in the DNS-maneuver + harness condition
than in the DNS-maneuver condition. Conclusion: Wearing a trunk harness could help stabilize the lumbopelvic region and changemuscle activity patterns.
Keywords: prone hip extension, lumbopelvic stability, muscle activity onset time, trunk harness, low back pain

IntroductionLow back pain accounts for a high percentage of cases ofchronic pain and is responsible for significant economic
losses worldwide; thus, the establishment of treatment andprevention methods for low back pain is essential.1 Decreased
lumbopelvic stability causes abnormal changes in theneuromusculoskeletal system, resulting in low back pain and its
recurrence.2,3Therefore,
suppressing
compensatory
lumbopelvic movements and stabilizing the lumbopelvic region
during therapeutic exercise is important in patients with low
back pain and lumbopelvic instability.
The prone hip extension (PHE) test has been used to evaluate
lumbopelvic stability. In patients with low back pain, excessive
lumbar lordosis, anterior tilt, and pelvis rotation are observed ascompensatory movements during PHE.4 These compensatory
movements are a characteristic pattern in patients with low backpain.3 In addition, overactivity of the erector spinae and delayed
onset time of the erector spinae and multifidus are characteristicfeatures of patients with low back pain.5,6
For patients with low back pain and lumbopelvic instability,
therapeutic exercises such as abdominal hollowing andabdominal bracing are available to decrease compensatory
Published by LMU Institutional Repository, 2023

movements.7 Abdominal hollowing aims to induce selective
contraction of the transverse abdominis by pulling the umbilicalregion, while abdominal bracing involves co-contraction of thepatients’ trunk muscles. Suehiro et al.8 found that abdominal
hollowing and abdominal bracing contributed to spinal
stabilization during PHE. However, previous studies wereconducted with healthy participants, and it is unclear whether
abdominal hollowing and abdominal bracing would have thesame effects on patients with low back pain. However, theeffects of abdominal bracing and abdominal hollowing on thespine are different, with abdominal hollowing having no direct
mechanical impact on the spine and abdominal bracing
promoting more effective stability patterns compared to AH.7
Thus, abdominal bracing may be the preferred method forindividuals with lumbopelvic instability. However, accurate
abdominal bracing requires feedback from physical therapists
or equipment such as an electromyography (EMG) unit, andthere is a report of high subjective difficulty of abdominal
bracing.9 On the other hand, Dynamic Neuromuscular
Stabilization (DNS) is a rehabilitative approach rooted inneurophysiology and developmental principles that involves
using a series of functional tests to assess different patterns of1

Asian Journal of Physical Therapy, Vol. 1 [2023], No. 2023, Art. 3
AJPT Toraiwa, Jaotawiparta, Suzukia, Kuruma

postural stabilization.10 DNS focuses on intra-abdominalpressure (IAP), which is beneficial because it is also used as an
exercise to improve postural stabilization patterns in various
limb positions and movements. Therefore, this study focusedon IAP in DNS to stabilize the lumbopelvic region. For thisstudy, the ‘DNS maneuver’ was defined as a technique with
instruction according to the DNS principle that results in acoordinated activity of the diaphragm, pelvic floor, andabdominal wall.11 In DNS, few people show an ideal pattern on
functional testing, and like abdominal bracing, it is a techniquewith challenges for accurate implementation10; therefore,
maintaining proper IAP and feedback by therapists is difficult.
Therefore, we hypothesized that wearing a trunk harness(Positive Motion Harness, Helinx) during movement could
improve the effect of IAP and deep stabilization system. The
trunk harness is an orthotic device made of elastic fibers
wrapped from the rib cage through the abdomen to the femoral
region. It may be useful in maintaining spine alignment. We
hypothesized that the trunk harness has several potential
advantages, such as assisting with muscle contraction,
stimulating proprioceptors in the abdomen through externalpressure, and reducing compensatory movements of the lumbar
spine and pelvis during movement. Notably, Miyazaki et al.12
reported that the thickness of the transversus abdominis
improved by applying tape, indicating that the activity of deep
trunk muscles may be changed with external stimulation.
However, the relationship between compensatory movementsof the lumbopelvic region during movement has not beenreported. Wearing the trunk harness may contribute to proper
spinal alignment, increase IAP, stabilize the lumbopelvic
region, and improve the delayed onset of lumbopelvic muscles.
The purpose of this study was to examine the effects ofperforming to improve DNS-maneuver with and without atrunk harness on the lumbopelvic stability and muscle activityof the trunk and hip joint muscles during PHE in healthy
individuals, as well as in patients with low back pain.
Methods
2.1 Participants
Thirty-one participants (15 healthy men and 16 men with low
back pain) were included in this study. The inclusion criteria
were male and 18 years of age or older. The exclusion criteria
were a history of lumbar spine or hip surgery and a diagnosis or
suspicion of serious spinal disease (inflammatory spinal
disease, fracture, malignancy, cauda equina syndrome, or
infection). Low back pain was defined as unilateral or bilateralpain between the 12th rib and the tailbone.13 The Japanese
Orthopedic Association Back Pain Evaluation Questionnaire(JOABPEQ) was used to identify patients with low back pain.
If the functional score after treatment exceeded 90 points, thetreatment was judged to be effective.14 Hence, patients whoscored below 90 on the pain-related disability score of
JOABPEQ were included. This study was reviewed andapproved by the Ethics Committee of Tokyo Metropolitan
University (20046). This study was performed by the tenets of
the Declaration of Helsinki, and written informed consent was
obtained from all participants.
2.2 Experimental Procedurehttps://digitalcommons.lmunet.edu/ajpt/vol1/iss2023/3

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The prone hip extension was performed with the participant’s
dominant leg, i.e., the one used for kicking. The starting
position of the PHE was prone to the hip joint at 30° flexion
with the knee extended. A target bar was placed at 10° hip
extension, and the participants were instructed to extend the hip
joint with a signal and hold a touch bar for 5 s (Figure 1).
Figure 1. Prone hip extension

The prone hip extension was performed under three conditions:control condition, DNS-maneuver condition, and DNSmaneuver + harness condition. The order of the DNS-maneuver
condition and the DNS-maneuver + harness condition was
randomized. In the control condition, only verbal commands
were provided. In the DNS-maneuver condition, participants
performed PHE after the verbal instruction, “Please perform the
movements while pushing with your abdominal wall andmaintain during the whole movement.” In the DNS-maneuver+ harness condition, participants were asked to perform PHE
with the trunk harness attached and, after the verbal instruction,“Please perform the movements while bulging your abdomenby pushing the abdominal belt and maintain during the whole
movement.” The trunk harness was wrapped as follows: thethoracic belt was set at the lower corner of the scapula, and theabdominal belt was crossed below the three lateral fingers ofthe xiphoid process and passed over the greater trochanter
Figure 2. Wearing the trunk harness

Note. The thoracic belt was at the lower corner of the scapula. The abdominal
belt was crossed below the three lateral fingers of the xiphoid process.

(Figure 2).
2Toraiwa et al.: Trunk harness effect on stability on prone hip extension
AJPT Toraiwa, Jaotawiparta, Suzukia, Kuruma

A pressure sensor (PG-100-102RP; Digi-Key Electronics, Inc.)was used to confirm that the pressure at the crossed region of
the belt was within 25–35 mmHg during resting expiration. A
3-minute break was provided between each measurement
condition to minimize carryover effects.
2.3 Data Processing
The measurement items were the pelvic motion angles, lumbar
lordosis angle, muscle onset time, difficulty of movement
during PHE, and JOABPEQ score. The pelvic motion angles
were measured using a three-dimensional motion analysis
system (Vicon Nexus, Vicon) with 12 cameras at a sampling
rate of 200 Hz. The reflective markers were placed at thefollowing sites: the T12 spinous process, L2 spinous process,bilateral anterior superior iliac spine (ASIS), bilateral posterior
superior iliac spine (PSIS), S1 spinous process, S3 spinous
process, and bilateral lateral femoral epicondyle. The reflective
markers on the bilateral ASIS were used to define the segmental
coordinate system, and the reflective markers on the bilateral
PSIS and sacral region were used to track the pelvic segments.
The segment definition method was based on a plug-in gait
model.15 The x-axis was defined as the line parallel to a line
connecting the ASIS and PSIS midpoints, and the pelvic
anterior tilt direction was defined as the positive direction. The
y-axis was defined as a line parallel to a line connecting theright and left ASIS, with the right pelvic oblique in the positive
direction. The z-axis was defined as the line perpendicular to
the x- and y-axes, and the left rotation direction was defined as
the positive direction. The pelvic oblique and rotation angles
were calculated such that oblique and rotation to the same sideof the moving leg were positive values. The pelvic motion
angles were defined as the difference between the mean values
obtained with 1 s of rest and 1 s of 5 s of PHE. The mean valueof five trials was used for the statistical analysis. Initiation oflower leg movement was defined as the point at which the
upward velocity of the lateral femoral epicondyle marker
exceeded 5% of the maximal velocity.16
The lumbar lordosis angle was measured using a curved ruler(flexible curved ruler with a 40-cm scale, Shinwa MeasurementCo.) The lumbar lordosis angles were measured by placing theruler on the participants' T12–S2 spinous process. The straightline connecting T12–S2 was set as L, while the perpendicularline from the midpoint of the curve to L was set as H. The
lumbar lordosis angle was measured by calculating 4Arctan(2H/L).17-19 The lumbar lordosis angle was defined as thedifference between the prone and PHE position angles. The
mean values of three trials were used for the statistical analysis.
Muscle onset time was measured using wireless dry Ag surface
electromyography (Delsys Trigno, Delsys, Inc.) with a 1.0 cm
center-to-center inter-electrode distance. The four-electrodeplacement was attached to locations based on the Surface
Electromyography for the Non-Invasive Assessment ofMuscles (SENIAM) recommendations 20: the bilateral erector
spinae (at a 2-finger-width distance lateral from the spinous
process of L1), gluteus maximus (50% on the line extending
between the sacrum and greater trochanter), andsemitendinosus (50% on the line extending between the ischial
tuberosity and medial epicondyle). The band-pass filter was set
to 20–450 Hz, and the measurement was performed at a
Published by LMU Institutional Repository, 2023

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sampling frequency of 1,000 Hz using an A/D converter(Giganet, VICON) of a three-dimensional motion analysis
system. Baseline processing and smoothing were performed
using the EMG analysis software (Delsys Analysis). To
determine the onset time of muscle activity, the threshold of
three standard deviations from the mean value observed atbaseline was calculated. The muscle onset time was defined as
the time when the EMG signal exceeded this threshold for morethan 50 ms. The muscle onset time was normalized based on theinitiation of the lower leg movement. Positive values indicatedthat muscle activity occurred later than the initiation of leg
movement. The mean value of five trials was used for statisticalanalysis. The difficulty of the movements was measured using
a visual analog scale. A value of 0 mm was classified as “veryeasy to raise” and 100 mm as “very difficult to raise.” Theseverity of low back pain was assessed using the JOABPEQ inboth groups. Difficulty was asked after each condition, and
JOABPEQ was inquired after all trials were completed.
2.4 Statistical Analysis
The results of the JOABPEQ were compared using the Mann–
Whitney U test. Repeated-measures two-way analysis ofvariance (ANOVA) was performed for each measurement item,with the participant group as a between-subjects factor and thedifference in maneuver as a within-subjects factor. A multiplecomparison method with Bonferroni adjustment was used as a
post-hoc test between the levels of factors that showed a main
effect. IBM SPSS Statistics ver. 26 was used for statisticalanalysis, and the significance level was set at 5%.
Results
Table 1 shows the demographic data and JOABPEQ results forboth groups. In JOABPEQ, the low back pain group showedsignificantly lower values for pain-related disability, lumbar
spine dysfunction, gait dysfunction, and social life disability (p< 0.05). Table 2 shows both groups' lumbopelvic motion angle,
motion difficulty, and muscle onset time. Repeated-measures
two-way ANOVA showed no main effect of group andinteraction. The maneuver showed significant main effects on
the difficulty of movement, lumbar lordosis angle, pelvic
anterior tilt angle, pelvic oblique angle, and muscle onset timeof gluteus maximus and contralateral erector spinae (p < 0.05)(Table 3). Post-hoc analysis showed that the lumbar lordosis
angle was significantly lower in the DNS-maneuver and DNSmaneuver + harness conditions than in the control condition (p< 0.05). The pelvic anterior tilt angle was significantly lower inthe DNS-maneuver + harness condition than in the control andthe DNS-maneuver conditions (p < 0.05). The pelvic obliqueangle was significantly lower in the DNS-maneuver condition
than in the control and the DNS-maneuver + harness conditions(p < 0.05). The muscle onset of GLUTEUS MAXIMUS andcontralateral erector spinae were lower in the DNS-maneuver +harness condition than in the control and DNS-maneuver
conditions (p < 0.05). The difficulty of the movements was
significantly lower in the DNS-maneuver and DNS-maneuver+ harness conditions than in the control condition (p < 0.05) andsignificantly lower in the DNS-maneuver + harness condition
than in the DNS-maneuver condition (p < 0.05) (Table 4).
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Asian Journal of Physical Therapy, Vol. 1 [2023], No. 2023, Art. 3
AJPT Toraiwa, Jaotawiparta, Suzukia, Kuruma

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Table 3. Repeated-measures two-way analysis of variance

Table 1. Demographic data and JOABPEQ scores in both groups
Low back pain

Healthy men (n = 15)Groupp-value Effect size (r)(n = 16)

ManeuverGroup*Maneuver

F value p-value

η2

F value p-value

η2

F value p-value

η2

Demographic data

Lumbar lordosis

<0.01

0.99

<0.01

17.42

<0.01*

0.38

0.14

0.71

<0.01

Age (years)

22.1 ± 2.5

20.6 ± 1.4--

Pelvic anterior tilt

2.31

0.14

0.07

9.44

<0.01*

0.25

0.16

0.85

<0.01

Height (cm)172.8 ± 6.4

174.6 ± 3.6--

Pelvic oblique

7.64

0.01

0.21

6.18

<0.01*

0.18

0.15

0.86

<0.01

Weight (kg)64.1 ± 12.6

67.6 ± 6.8--

Pelvic rotation

2.28

0.14

0.07

0.42

0.66

<0.01

0.01

0.99

<0.01

-

Difficulty of PHE

0.05

0.82

<0.01

44.85

<0.01*

0.61

0.99

0.38

0.03

JOABPEQ (points)

Gluteus maximus

0.24

0.63

<0.01

17.09

<0.01*

0.37

2.3

0.11

0.07

Pain-related disability score100.0 (100.0–100.0)

71.0 (43.0–71.0)<0.01*

0.92

Semitendinosus

1.59

0.22

0.05

1.05

0.36

0.03

0.54

0.59

0.02

Lumbar dysfunction score100.0 (100.0–100.0)

91.5 (81.0–100.0)

0.02*

0.56

Ipsilateral ES

0.18

0.68

<0.01

0.24

0.79

<0.01

0.16

0.85

<0.01

Gait dysfunction score100.0 (100.0–100.0)

100.0 (98.3–100.0)

0.04*

0.37

Contralateral ES

0.1

0.75

<0.01

5.02

0.01*

0.15

1.76

0.18

0.06

Right dominant leg (men)

13

13

-

Social life disability score100.0 (96.0–100.0)

81.0 (76.8–100.0)

0.01*

0.46

Psychological disability score76.0 (57.0–85.0)

80.5 (72.0–89.3)

0.41

0.15

Note. Demographic data are described as values with mean±standard deviation, JOABPEQ data aredescribed as values with median and 25–75 percentile values; JOABPEQ = Japanese Orthopedic
Association Back Pain Evaluation Questionnaire*: p < 0.05

Table 2. Lumbopelvic motion angle, motion difficulty, and muscle onset time in both groups
Healthy men (n = 15)

Low back pain (n = 16)

DNS-M

DNS-M +
harness

Control

DNS-M

DNS-M +
harness

Lumbar lordosis

7.30 ± 3.52 5.86 ± 2.94

3.78 ± 4.63

8.21 ± 2.65 5.10 ± 4.33

3.93 ± 3.38

Pelvis anterior tilt

6.63 ± 2.91 6.35 ± 3.15

5.06 ± 2.93

8.21 ± 2.65 8.27 ± 3.66

6.53 ± 3.72

Control
Kinematic data (°)

Pelvis oblique
Pelvis rotation
Difficulty (mm)Muscle onset time(ms)

2.61 ± 4.26 1.63 ± 4.07 2.90 ± 4.86 2.09 ± 3.98 1.24 ± 4.48 2.15 ± 3.62
−1.86 ±
−0.79 ±
−1.86 ± 1.78 −2.02 ± 2.21
−0.86 ± 1.94 −0.98 ± 2.14
1.80
1.78
45.2 ± 19.3 32.3 ± 21.2 22.7 ± 20.4 47.2 ± 19.1 27.1 ± 14.9 21.8 ± 17.4

−37.4 ±
−1.94 ±
−25.1 ±
−103.9 ± 91.4
−50.3 ± 81.9 −104.2 ± 51.5
54.7
110.8
82.2
−191.9 ± −205.8 ±−145.9 ±−174.6 ±Semitendinosus−192.7 ± 54.5
−178.9 ± 64.9
55.8
95.8
66.6
122.6
−153.6 ± −156.4 ±−148.1 ±−172.0 ±Ipsilateral ES−155.3± 97.0
−170.3 ± 58.4
48.6
123.5
89.8
71.6
−140.6 ± −161.9 ±−103.0 ±−184.9 ±Contralateral ES−169.3 ± 182.2−215.5 ± 90.2
42.4
123.5
99.3
112.5
Note. Values are mean ± standard deviation; IAP-M = intra-abdominal pressure-maneuver; ES =erector spina
Gluteus maximus

https://digitalcommons.lmunet.edu/ajpt/vol1/iss2023/3

Note. ES = erector spinae, PHE = prone hip extension* p < 0.05 z
Table 4. Post-hoc analysis
Control vs. DNS-M +DNS-Mvs. DNS-M +harness
harness
Mean
EffectMean
EffectMean
Effectp-valuep-valuep-valuedifference
size (d) difference
size (d) difference
size (d)Lumbar
2.17 (0.75,
3.80 (1.96,
1.63 (−0.01,<0.01* 0.61
<0.01* 1.01
0.05
0.41
lordosis
3.60)
5.64)
3.26)
Pelvic anterior 0.11 (−1.06,
1.63 (0.64,
1.52 (0.50,
1
0.03<0.01* 0.5<0.01* 0.43
tilt
1.29)
2.61)
2.53)
−0.17
−1.09
0.92 (0.09,
Pelvic oblique
0.03* 0.21
1
0.04
0.02* 0.25(−1.75,(−2.04,1.75)
0.57)−0.14)
0.03 (−0.3,
0.16 (−0.36,
0.14 (−0.40,
Pelvic rotation
1
0.02
1
0.08
1
0.07
0.71)
0.68)
0.50)
Difficulty of
23.97
16.48 (1.81,
7.49 (0.55,<0.01* 0.87
<0.01* 0.39
performing(16.93, <0.01* 1.24
22.15)
14.43)
PHE
31.01)
−5.07
72.90
77.97
Gluteus10.05
1(−44.95,(38.72, <0.01*(38.54, <0.01* 0.87
maximus34.81)
107.07)117.39)
21.34
16.89
−4.45
Semi0.86
0.23
0.44
0.27
1
0.05
(−28.50,(−11.82,(−41.65,
tendinosis
71.18)
45.59)
32.75)
13.35
11.96
−1.39
Ipsilateral ES (−42.81,
1
0.15
1
0.16
1
0.02
(−39.02,(−57.20,69.512)61.93)
54.41)
51.62
18.93
Contralateral
70.56 (3.07,
0.75
0.52
0.04* 0.61
1
0.15(−0.23,(−36.33,
138.05)
ES
103.47)74.19)
Control vs. DNS-M

Note. Values are described as mean differences with 95% confidence intervals; AB = abdominal
bracing, ES = erector spinae, PHE = prone hip extension*: p < 0.05

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Toraiwa et al.: Trunk harness effect on stability on prone hip extension
AJPT Toraiwa, Jaotawiparta, Suzukia, Kuruma

Discussion
The decrease in lumbar lordosis angle observed in the DNSmaneuver, and DNS-maneuver + harness conditions may result
from lumbar stabilization due to activation of the abdominal
muscle groups. Suehiro et al.8 reported that the lumbar lordosis
angle decreased significantly during PHE with abdominal
hollowing and abdominal bracing compared to the normal
condition, and abdominal muscles showed the highest muscle
activity in the abdominal bracing condition. In this study, theabdominal muscles might have been activated in the DNSmaneuver and DNS-maneuver + harness conditions, reducing
the lumbar lordosis angle. In the DNS-maneuver + harness
condition, the anterior pelvic tilt angle significantly decreased,
which implies that the lumbopelvic region was stabilized to agreater degree in the DNS-maneuver + harness condition thanin the other conditions. The trunk harness originated from therib cage, crossed at the abdomen, and wrapped around the hip
joint. Thus, the spinal column was thought to be stabilized bywrapping, e.g., by the external pressure of the thorax to the hip
joint. In addition, in the DNS-maneuver + harness condition,
the participants performed PHE by pushing the abdominal belt.
Therefore, we consider it more straightforward to stimulate thecontraction of the abdominal muscles when wearing the trunk
harness because it is easier for patients to be aware of theirabdomen muscles when feeling the external pressure from thetrunk harness. For these reasons, the DNS-maneuver + harness
condition was more likely to increase the activity of theabdominal muscle groups than the DNS-maneuver condition,
resulting in a significant decrease in the anterior pelvic tilt
angle.
The onset of gluteus maximus in the harness condition was
significantly earlier than in the other conditions, and the onsetof contralateral erector spinae was considerably earlier than thatin the control condition. The multifidus and contralateralerector spinae activity in PHE is a feed-forward controlled
activity.6 Moreover, a significant correlation has been reported
between the amount of anterior pelvic tilt angle and the delayin the onset of bilateral multifidus and contralateral erector
spinae during PHE.6 The delay in the onset of gluteus maximus
is associated with abnormal movements, such as excessive
lumbar lordosis and rotation during PHE, even in healthy
individuals.21 Therefore, altering the onset time of muscle
activity in the DNS-maneuver + harness condition isadvantageous for stabilizing the lumbopelvic region. The
factors contributing to these changes might be the stabilizationof the lumbopelvic region in the DNS-maneuver + harness
condition, greater stimulating activity of the abdominal
muscles, and the change in the lumbar lordosis angle. The onset
time of gluteus maximus was accelerated in PHE with AH,22
and training for neuromuscular control of the lumbopelvic
region and hip joint affects muscle activity patterns. In thisstudy, the lumbopelvic region was stabilized, and the muscle
activity pattern was improved in the DNS-maneuver + harness
condition compared to the DNS-maneuver condition. These
results suggest that the trunk harness may help improve
lumbopelvic stability and muscle activity patterns.

Published by LMU Institutional Repository, 2023

5This study showed no decrease in the anterior pelvic tilt angle
or muscle onset time in the DNS-maneuver condition. These
results differ from those of several previous studies,8,22 possibly
because of differences in the intervention methods used inprevious studies. Previous studies employed feedback using
surface EMG and pressure biofeedback devices to perform
abdominal hollowing and AB accurately.8,22 In this study, only
verbal instructions were provided for the DNS-maneuver, andDNS-maneuver + harness conditions. We did not use
ultrasound imaging to check whether the DNS-maneuver was
accurately performed. As a result, some participants may havebeen unable to increase trunk muscle activity and IAP during
the DNS-maneuver condition. These results suggest that theaccurate performance of abdominal hollowing, abdominal
bracing or DNS-manuever may be difficult without feedback.
In the DNS-maneuver + harness condition, participants pushed
the abdominal belt, which may have facilitated the focusing of
the abdominal muscles, including the deep trunk muscles. As aresult, the difficulty of the movements decreased more in the
DNS-maneuver + harness condition than in the otherconditions. These results suggest that wearing a trunk harness
is more effective in stabilizing the lumbopelvic region andimproving muscle activity patterns during PHE than inconventional abdominal hollowing and abdominal bracing
conditions.
This study showed no significant differences between healthy
individuals and patients with low back pain in eachmeasurement item, except for the JOABPEQ scores. This may
be because the patients with low back pain in this study
included those with mild conditions and those who did not havelumbopelvic instability. This study used a questionnaire survey
among university students and adults to select patients with low
back pain. Still, the pain in most of these patients did notinterfere with their daily lives. Therefore, many of theparticipants in this study had relatively mild LBP; thus, there
were no significant differences between healthy individuals andpatients with low back pain. Sahrmann4 reported that excessive
lumbar lordosis and excessive anterior tilt and rotation of thepelvis are compensatory movements during PHE in patientswith low back pain during clinical observation. However, theangle of lumbar lordosis is significantly decreased in thesepatients,17 and the angle of lumbar lordosis decreases during
movement in patients with non-specific chronic low backpain.18 Therefore, there is no standardized view on the
movement of the lumbopelvic region during PHE in individuals
with low back pain. One of the reasons for this is the need tosubgroup patients with low back pain. In recent years, theimportance of subgrouping patients with low back pain has
been discussed.23 Some patients have hypermobility or
hypomobility of the lumbar spine.24 In this study, we did notevaluate the mobility of the lumbar spine; therefore, patientswith hypermobility and hypomobility may have been included
as participants. As a result, no significant difference wasobserved between healthy individuals and patients with low
back pain. However, there is no gold standard measure forlumbopelvic instability, and it is necessary to consider amultidimensional perspective.25 This study also showed that
lumbar kinematic patterns were similar in both groups,
indicating that muscle activation and lumbar kinematic patterns
are not as important as previously discussed. In the future, it
5Asian Journal of Physical Therapy, Vol. 1 [2023], No. 2023, Art. 3
AJPT Toraiwa, Jaotawiparta, Suzukia, Kuruma

6

will be necessary to investigate the effectiveness of exercise
therapy with trunk harnesses in patients with low back pain who
are selected using more rigorous eligibility criteria.

10.

Kobesova A, Davidek P, Morris CE, et al. Functional posturalstabilization tests according to Dynamic Neuromuscular Stabilization
approach: Proposal of novel examination protocol. J Bodyw Mov Ther.
2020;24(3):84-95. doi:10.1016/j.jbmt.2020.01.009

This study had some limitations. First, we did not measure theactivities of deep trunk muscles such as the multifidus andtransversus abdominis muscles. Second, we did not conduct
long-term intervention studies using the trunk harness;therefore, the harness's long-term effect is unclear. Further, theparticipants of this study were young; hence, further
investigation of the broader population is needed to generalize
the results. Lastly, we did not classify participants with low
back pain based on the mobility of the lumbar spine, and we
may have included patients with mild low back pain. In the
future, it will be necessary to examine the effects of lumbar
stabilization exercises using a trunk harness on the deep trunk
muscles with a long-term intervention.

11.

Madle K, Svoboda P, Stribrny M, et al. Abdominal wall tension
increases using Dynamic Neuromuscular Stabilization principles indifferent postural positions. Musculoskelet Sci Pract. 2022;62:102655.
doi:10.1016/j.msksp.2022.102655

12.

Miyazaki T, Matsui T, Seo K, et al. Trial of the contraction method fortransversus abdominal muscle with taping: Focusing on the muscle
thickness of external oblique, internal oblique and transversus abdominal
muscles. J Phys Fit Sports Med. 2019;68(1):65–69. doi:
10.7600/jspfsm.68.65

13.

Shirado O, Arai Y, Iguchi T, et al. Formulation of Japanese Orthopaedic
Association (JOA) clinical practice guideline for the management of low
back pain- the revised 2019 edition. J Orthop Sci. 2022;27(1):3-30.
doi:10.1016/j.jos.2021.06.024

14.

Hashizume H, Konno S, Takeshita K, et al. Japanese orthopaedic
association back pain evaluation questionnaire (JOABPEQ) as an
outcome measure for patients with low back pain: reference values inhealthy volunteers. J Orthop Sci. 2015;20(2):264-280.
doi:10.1007/s00776-014-0693-1

15.

Davis RB, Õunpuu S, Tyburski D, et al. A gait analysis data collection
and reduction technique. Hum Mov Sci. 1991;10(1):575–587. doi:
10.1016/0167-9457(91)90046-Z

16.

Tateuchi H, Taniguchi M, Mori N, Ichihashi N. Balance of hip and trunk
muscle activity is associated with increased anterior pelvic tilt during
prone hip extension. J Electromyogr Kinesiol. 2012;22(3):391-397.
doi:10.1016/j.jelekin.2012.03.003

17.

Arab AM, Haghighat A, Amiri Z, Khosravi F. Lumbar lordosis in prone
position and prone hip extension test: comparison between subjects withand without low back pain. Chiropr Man Therap. 2017;25:8. Published2017 Mar 16. doi:10.1186/s12998-017-0139-x

18.

Pourahmadi M, Takamjani IE, Sarrafzadeh J, et al. Effect of Chronic
Low Back Pain on Lumbar Spine Lordosis During Sit-to-Stand andStand-to-Sit. J Manipulative Physiol Ther. 2020;43(2):79-92.
doi:10.1016/j.jmpt.2018.11.028

Conclusion
In the present study, we compared lumbopelvic motion andtrunk hip muscle activity during PHE in healthy individuals andpatients with low back pain using a trunk harness. The results
showed that wearing the trunk harness effectively stabilizes thepelvic region and changes muscle activity patterns.
Conflicts of Interest
The authors have no conflicts of interest to declare.
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