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The effect of frontpacks, shoulder bags and handheld bags on 3D back shape and posture in young university students: An ISIS2 study

June 2012
Studies in Health Technology and Informatics 176:117-21

Source
PubMed

Authors:

Teesside University

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. 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. The Integrated Shape Imaging System 2 (ISIS 2) was used to evaluate 3 D back shape and posture. 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. 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.

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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

Abstract.

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

1. Introduction

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 [1]. 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 [3]. 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 [3]. Back pain in adolescents is associated with long

term back pain [4].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 [5] and Negrini et al [7] reported trunk flexion in response to load carried

in a backpack, the extent of which varies between ergonomic and standard bags.

Motmans et al [8] and O`Shea et al [6]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 [9] 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.

2. Objective

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.

3. Participants:

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.

4. Materials

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

Characteristics

Means and Standard Deviations

Age

23.85 ± 4.120232 (Years)

Height

172.95 ± 11.73041 (CM)

Weight

70.55 ± 17.76299 (KG)

BMI

24.645 ± 5.499902

Female

Male

Left Handed

Right Handed

Telescopic actuator

Camera

Projector

Figure 1: The ISIS2 SYSTEM

5. Results

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

volumetric asymmetry.

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 [5]. 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 [6]

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.

7. References

1. Christie et al, 1995; Christie , H.J., Kumar, S., Warren, S.A. (1995). Postural aberrations in low

back pain. American congress of rehabilitation medicine and the American academy of physical

med and rehabilitation. 76: 218-224.

2. Griegel- Morris et al, 1992 Griegel- Morris, P., Larson, K., Mueller- Kiaus, K., Oatis, C.A.

(1992).Incidence of common postural abnormalities in the cervical, shoulder and thoracic regions

and their association with pain in two age groups of healthy subjects. Physical therapy. 72(6):

424-431.

3. NICE Guidelines, 2009 http://www.nice.org.uk/nicemedia/pdf/CG88fullguideline.pdf

4. Siambanes, D., Martinez, J.W., Butler, E.W., Haider, T. (2004). Influence of school backpacks on

adolescent back pain. Journal of paediatric orthopaedics. 24(2): 221-217

5. Bettany- Saltikov, J., Warren, J., Stamp, M. (2008). Carrying a rucksack on either shoulder or the

back, does it matter? Load induced functional scoliosis in normal young subjects. Research into

spinal deformities 6. IOS Press. 221-224.

6. O'Shea C, Bettany-Saltikov JA, Warren JG.Effect of same-sided and cross-body load carriage on

3D back shape in young adults.

7. Negrini, S., Negrini, A. (2007). Postural effects of symmetrical and asymmetrical loads on the

spines of school children. Scoliosis. 2(8):1-7.

8. Motmans et Motmans, R.R.E.E., Tomlow, S., Vissers, D.( 2006). Trunk muscle activity in

different mode of carrying schoolbags. Ergonomics. 49(2): 127-138.

9. Zultowoski and Aruin Zultowski, I., Ariun, A. (2008). Carrying loads and postural sway in

standing: the effect of load placement and magnitude. Ios press. 30:359-36

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Jan 2006
Stud Health Tech Informat

Regular carriage of heavy loads such as backpacks, satchels and mailbags results in a variety of acute medical problems and increased potential for back injury. There is a paucity of information about the specific changes in back posture that occur in response to asymmetrical loading. The purpose of this study was to examine the changes in back shape that occurred in response to asymmetrical load carriage, either on one shoulder (same-side) or across the body (cross-body), in healthy young adults. A convenience sample of 21 physiotherapy students randomly performed three trials (unloaded, same-side loaded, cross-body loaded) in standing with a 15% body load. The Microscribe 3DX digitiser (Immersion Group Ltd) recorded the three dimensional coordinates of 15 Key anatomical landmarks on the back in the three conditions. A one-way ANOVA with repeated measures and post-hoc tests was implemented to highlight statistical differences in the data collected (p<0.05). Significant differences were found in the x, y and z coordinates of the anatomical landmarks in the upper back between unloaded and loaded conditions. Results demonstrated significantly less impact on spinal posture from cross-body loading as compared to same-sided loading. This study confirms that there are significant three-dimensional changes in back shape in response to asymmetrical loading. Further work is needed to evaluate the optimal carriage type and maximal body load that results in the least spinal impact and injury potential in young adults.