The effect of Frontpacks,Shoulder bags and
Handheld bags on 3D back shape and
posture in young university students:
An ISIS2 study
Bettany-Saltikov J 1* and Cole L 2
Teesside University, Institute of Health and Social Care,Parkside west
offices Middlesbrough, TS1 3BA, UK,12
Background: Students at school and university settings have been shown to carry heavy loads in a variety of
pack systems. Both type and mode of load carriage have been shown to cause significant postural adaptations
that can lead to injuries in the shoulder, arms, hands and back. Whilst backpacks have been well researched,
there is a paucity of literature on the effects of frontpacks, shoulder bags and hand-held bags on 3D posture
and back shape.
Objective: The objective of this study was to evaluate the effect of carrying three different types of bag
(shoulder, front and handheld), each containing a load of 15% body weight.
Materials: The Integrated Shape Imaging System 2 (ISIS 2) was used to evaluate
3 D back shape and posture.
Participants: The study involved twenty-five university students. A repeated measures design was used to
record the effects of four conditions using no load (reference), a frontpack, a shoulder bag and a handheld
bag. Measurements with ISIS 2 were taken 5 minutes post loading. All of the conditions were randomised in
an attempt to offset any order effects.
Results showed an increase in extension and lumber lordosis angles for the front bag (P<0.001) and an
increase in flexion and reduced lumber lordosis in the shoulder and hand held bags (p<0.05). Kyphosis
curves were also significantly increased in the hand held bag (p<0.006). Right unilateral load carriage also
demonstrated the greatest right volumetric asymmetry.
Discussion: Bilateral front carriage as supported by previous literature produces a symmetrical shift away
from the load. Unilateral carriage however produces an asymmetrical deviation away from the load which
results in significant postural deviations and adaptations.
Conclusion :Frontbags may be more suitable for load carriage within the young adult student population as
they produce a symmetrical postural deviation in one plane in response to load. The shoulder and handheld
bags produce postural deviations in all planes which may cause adverse stress and strain on spinal structures
and ultimately lead to pain and progressive postural scoliosis.
Keywords. Backshape, posture, ISIS2, topographical scanning, load carriage
Load carrying systems are commonly used within recreational and occupational settings,
with bags in particular routinely used throughout most of the educational years at school,
college and university to transport heavy books and stationary . The link between
load carriage and musculoskeletal pain in the neck, back and shoulders has been well
documented [2,3] with prevalence of back pain documented to be as high as 30-51% in
adolescent students and requiring 4-31% to seek medical intervention . Prevalence
in children has been shown to be near to that in adults with 1 in 3 individuals affected in
the UK, with 20% seeking medical consultation and causing an estimated £1,632
million burden to the NHS in 1998 . Back pain in adolescents is associated with long
term back pain .The application of an external load, such as with a rucksack, causes
significant postural deviations in response to the compensational shift in the bodies’
centre of gravity (COG) within the base of support (BOS) [5,6]. The actual mode of
load carriage has been shown to cause different postural shifts resulting in adverse
stress and strains on the surrounding spinal structures resulting in back pain. Bettany-
Saltikov et al  and Negrini et al  reported trunk flexion in response to load carried
in a backpack, the extent of which varies between ergonomic and standard bags.
Motmans et al  and O`Shea et al reported lateral deviation in the frontal plane (i.e.
a spinal curve concave/ convex within the frontal plane) in response to a bag carried on
one shoulder whilst Zultowoski and Aruin  reported increased medial/lateral postural
sway when carrying a hand held brief case. There is however a distinct lack of research
into specific spinal curve angles in front bags and hand held loads despite wide use
within the military, manual labour occupations, college students` as well as the
population at large.
The objective of this study was to evaluate the effect of carrying three different types of
bag (front, right shoulder, and right handheld), each containing a load of 15% body
weight on 3D back shape and posture.
The study involved twenty-five university students. A repeated measures design was
used to record the effect of four different loading conditions; no load (reference), a
frontpack, a right shoulder bag and a right handheld bag. Measurements with ISIS 2
were taken 5 minutes post loading. All the conditions were randomised in an attempt to
offset any order effects. The mean characteristics of participants within the study are
presented in table 1.
The ISIS 2 equipment measures the 3D shape of the spine by capturing (with the
camera) the distorted patterns of parallel fringes that are projected onto the participants
back, allowing distances and height between the participant and reference screen to be
calculated incorporating crossed-optical-axis geometry on the user interface. From the
results a scan was produced showing visual interpretations of calculated parameters and
explanations of parameters.
Table 1: The mean characteristics for the 20 participants
Means and Standard Deviations
23.85 ± 4.120232 (Years)
172.95 ± 11.73041 (CM)
70.55 ± 17.76299 (KG)
24.645 ± 5.499902
Figure 1: The ISIS2 SYSTEM
A One Way ANOVA (Repeated measures) and a post-hoc Bonferroni test was
performed. Although changes were seen in most parameters the results showed no
overall statistically significant differences in back length, rotation, imbalance, Min skin
angle and Left and right Lateral Asymmetry angles (p>0.05). Results also showed an
increase in extension and lumber lordosis angles for the front bag (P<0.001) and an
increase in flexion and reduced lumber lordosis in the shoulder and hand held bags
(p<0.05). Kyphosis curves were also significantly increased in the hand held bag
(p<0.006). Right unilateral load carriage also demonstrated the greatest right
Figure 2: Example of the ISIS2 scans of one subject with from top left, no load, top right, frontpack,
bottom left, right shoulder bag and and bottom right, right hand held bag
6. Discussion and conclusions:
As expected all types load carriage types produced postural deviations, with
asymmetrical loads causing significantly greater deviations than symmetrical loads.
Bilateral front carriage as supported by previous literature produces a symmetrical shift
away from the load resulting in spinal extension. Unilateral loading modes produced
asymmetrical deviations away from the load which resulted in significant greater
postural deviations and adaptations than symmetrical loading. Previous studies
conducted at this centre compared symmetrical loading on the back to asymmetrical
loading of both shoulders, to investigate the effects of carrying a rucksack (on each
shoulder) on 3D spinal curvature in healthy young students . Carrying the load on
both shoulders resulted in no difference in the frontal plane angle but significantly
decreased the thoracic kyphosis in the sagittal plane. However, carrying the load on the
right shoulder significantly increased the thoracic lateral curvature in the frontal plane
and decreased the thoracic kyphosis in the sagittal plane. A study by O`shea et al 
further evaluated load carriage in asymmetrical postures; [either on one shoulder
(same-side) or across the body (cross-body)] in healthy young adults. Results
demonstrated significantly less impact on spinal posture from cross-body loading as
compared to same-sided loading. In conclusion, the limitations of the current study
included the lack of a sample size calculation before the study was conducted and the
small numbers of participants which may have resulted in a type 2 error (this is where
no significant differences are seen in some parameters when true differences do exist).
In the current study symmetrical frontbags caused significantly less postural deviations
than either shoulder or handheld asymmetrical modes of carriage. The shoulder and
handheld bags produced postural deviations in all planes which may cause adverse
stress and strain on spinal structures and ultimately lead to pain and progressive
postural scoliosis. There was a definite trend towards greater postural deviations using
a carrier bag than a shoulder bag.
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