Journal of Back and Musculoskeletal Rehabilitation 29 (2016) 109–115 109 DOI 10.3233/BMR-150605 IOS Press Effect of single and double backpack strap loading on gait and perceived exertion of young adults Ukachukwu Okoroafor Abaraogu ∗ , Wisdom Onyedikachi Ugwa, Ezinne Onwuka and Ebubechukwu Orji Department of Medical Rehabilitation, Faculty of Health Science and Technology, College of Medicine, University of Nigeria, Enugu Campus, Enugu, Nigeria Abstract. BACKGROUND/AIM: Backpack effect posture, walking and physiological costs but there is dearth of literature on effects of backpack strap (1 versus 2 straps) on gait and perceived exertion among young adults. We determined the influence of type of backpack shoulder strap on gait parameters and perceived exertion of young adults in a free-living normal walking speed. METHODS: Twenty-five young adults with a mean age of 22 years underwent a self-selected normal speed walking for six minutes each under 3 testing conditions: without a backpack; with 1 strap; and with 2 straps. Selected gait parameters and perceived exertion were assessed. RESULTS: There were no significant difference in stride length, stride time, step length, step time, gait speed, and cadence among the three walking conditions. However, perceived exertions were significantly higher when the backpack was carried with 15% irrespective of 1 strap or 2 straps. CONCLUSION: Momentary carriage of a backpack either on 1 strap or 2 straps does not appear to influence gait phases. However, this short bout of normal walking appear to increase perceived exertion in young adults irrespective of whether the backpack is wore on single or double shoulder strap. Keywords: Backpack load, backpack strap, young adults, perceived exertion, human gait 1. Introduction People use bags to carry various items they need in daily life. Young adult students use backpacks, which are usually carried over their shoulders [1,2]. Overly heavy bags and inadequate carrying methods may dis- tribute the weight inappropriately causing abnormal posture [3]. From a biomechanical perspective, abnor- mal posture begets abnormal gait pattern. However, as people habitually carry backpacks, they tend to neglect potential problems that could be associated to back- * Corresponding author: Ukachukwu Okoroafor Abaraogu, De- partment of Medical Rehabilitation, College of Medicine, Univer- sity of Nigeria, Enugu Campus, Enugu, Nigeria. E-mail: ukachukwu. abaraogu@unn.edu.ng, uabaraogu@yahoo.com. packs and how they are carried on the body. Succinctly put, as movement of backpack and walking are cor- related, the importance of possible untoward effect of backpack carriage and method on walking cannot be over emphasized. Several studies have reported alteration in gait pa- rameters associated with backpack use but these inves- tigations were largely among children and adolescents. Cottalorda et al. found that although there were no dif- ferences in gait parameters among children during sin- gle strap shoulder loading compared to double strap, the gait parameters difered when wearing a backpack compared to walking without a backpack [4]. In con- trast, a study among adolescents, found out that stride frequency increased while stride length decreased and concluded that carrying back pack on 1 shoulder sig- ISSN 1053-8127/16/$35.00 c  2016 – IOS Press and the authors. All rights reserved AUTHOR COPY