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

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.