INTRODUCTION

As college students we are interested in the effects that carrying a heavy backpack has on gait. We also are interested in the segment and joint angle deviations for carrying a backpack on one shoulder versus two. Research suggests that joint and segment angles will be altered when carrying a load, indicating a forward lean (Pascoe et al., 1997). Bone-on-bone forces have been calculated in other research to determine the long term effects of loaded walking. Peak bones forces at the hip and knee were found to be much greater than body weight (Simonsen et al., 1995). Studies also show that there is a tendency for stiffness to increase in one's back as the load they are carrying increases (Lee et al., 1997). This may be the result of nonlinear forces acting on the body. For this reason, we chose to analyze the differences in distributing load between both shoulders as opposed to one shoulder. The increased load will be more localized to a particular region of the trunk when carrying a backpack on one shoulder. On the other hand, when the backpack is worn on both shoulders the load is distributed more evenly across the trunk.

In this study we intend to prove that there are significant differences in human gait when a person carries a backpack on one shoulder instead of both shoulders. Our purpose for this study is to be able to make recommendations to fellow students regarding backpack use. To determine this we have videotaped a subject walking between two reference points in the situations aforementioned. The study will focus on the modifications made in the trunk, hip and knee in order to compensate for the two load distributions.