Evaluation of load carriage systems used by active duty police officers: Relative effects on walking patterns and perceived comfort Nerrolyn Ramstrand a, * , Roland Zügner b , Louise Bæk Larsen a , Roy Tranberg a, b a School of Health Sciences, J€ onk€ oping University, Sweden b Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University, G€ oteborg, Sweden article info Article history: Received 6 March 2015 Received in revised form 14 August 2015 Accepted 18 August 2015 Available online xxx Keyterms: Load bearing vest Equipment Kinematics Temporospatial Musculoskeletal disorders Biomechanics Ergonomics Law enforcement abstract Objectives: This study aimed to examine the effects of two different load carriage systems on gait ki- nematics, temporospatial gait parameters and self-reported comfort in Swedish police. Methods: 21 active duty police officers were recruited for this crossover study design. Biomechanical and self-report data was collected on two testing occasions. On occasion 1, three dimensional kinematic data was collected while police wore a/no equipment (control), b/their standard issues belt and ballistic protection vest and c/a load bearing vest with ballistic protection vest. Police then wore the load bearing vest for a minimum of 3 months before the second testing occasion. Results: The load bearing vest was associated with a significant reduction in range of motion of the trunk, pelvis and hip joints. Biomechanical changes associated with the load bearing vest appeared to reduce with increased wear time. In both the standard issue belt condition and the load bearing vest condition, police walked with the arms held in a significantly greater degree of abduction. Self-report data indicated a preference for the load bearing vest. Conclusion: The two load carriage designs tested in this study were found to significantly alter gait ki- nematics. The load bearing vest design was associated with the greatest number of kinematic com- pensations however these reduced over time as police became more accustomed to the design. Results from this study do not support selection of one load carriage design over the other and providing in- dividuals with the option to choose a load carriage design is considered appropriate. © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved. 1. Introduction As an occupational group police have been reported to experi- ence a high incidence of musculoskeletal injuries with low back pain being the most commonly reported condition (Nabeel et al., 2007; Jahani et al., 2002). In Swedish police, low back pain expe- rienced one day per week or more, is reported by 43% of active duty officers (Elgmark et al., 2013). In the Swedish general working population this figure is 29% (Arbetsmilj€ overket, 2011). Evidence is increasingly suggesting that the underlying cause of musculoskel- etal injury in police is associated with the requirement to wear heavy ballistic protection vests and carry equipment belts (Burton et al., 1996). Given that there is an established link between load carriage and low back pain (Picavet and Schouten, 2000; Orloff and Rapp, 2004), it is considered important to determine how the load carried by police affects performance of tasks typically encountered in policing. This information could significantly aid future re- searchers in the development of safer and healthier load carriage designs for police. The uniform of a police officer has a great impact on how they are perceived. The colour of the material, style of clothes and equipment carried all have an influence on how police are perceived by the general public (Johnson, 17th June 2015). A standardised uniform for police can be dated back to the early 1800's (Johnson, 17th June 2015) and has been adopted by police forces worldwide. While a standard uniform for all police ensures that they are highly recognizable to the general public, it also means that changes in uniform come at a great economic cost and must be carefully considered. The Swedish police force issues all active duty officers with equipment belts to be worn around the waist for the carriage of mandatory equipment (pistol, extra ammunition, torch, handcuffs, pepper spray, radio, and baton). The belts are fabricated from * Corresponding author. School of Health Sciences, PO Box 1026, 551 11 J€ onk€ oping, Sweden. E-mail address: Nerrolyn.ramstrand@ju.se (N. Ramstrand). Contents lists available at ScienceDirect Applied Ergonomics journal homepage: www.elsevier.com/locate/apergo http://dx.doi.org/10.1016/j.apergo.2015.08.007 0003-6870/© 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved. Applied Ergonomics 53 (2016) 36e43