Abstract
The purpose of this paper is to test the suitability of a modified backpack that distributes the carrying loads on the school children's chest and back. Sixty one (7.4 yr +/- 0.97), sixty (11.7 yr +/- 1.05), fifty eight (15.7 yr +/- 1.18) and fifty nine (18.9 yr +/- 1.45) school children were participated in the study representing the first, second, third and fourth group, respectively. They carried 0%, 5%, 10%, 15%, 20% and 25% of body weight in both commercial and modified backpacks while walking for 5 min. Main response measures were normalized rectus abdominus and erector spinae muscular activities, exertion ratings and cardiac cost, which is defined as the difference between heart rate of last walking minute and standing heart rate. The stresses on rectus abdominus and erector spinae muscles while wearing commercial backpack were significantly higher than those when participants worn modified backpack. Cardiac costs were significantly less in the case of the modified backpack compared to the commercial backpack case. Also, participants felt more comfortable while wearing the modified backpack compared to wearing commercial backpack. This paper showed that modified backpack was superior to commercial backpack in terms of less muscular activities, less cardiac costs and less exertion ratings. Moreover, the proposed design prevents the students from carrying their loads in one side. This study provides the community with a modified backpack that increases comfort and decreases pain. The student's preference of backpack may change when they use it.
Relevance to industry: The issue of backpack safety is getting more and more attention among health care professionals. This article discusses and proposes a new designed backpack which is superior to the traditional backpack in terms of less muscular activities, less cardiac costs, and less exertion ratings. This study provides the community with a new backpack that increases comfort, decreases pain, and occupational illness. (C) 2013 Elsevier B.V. All rights reserved.