INTRODUCTION

Being an expectant mother in her third trimester can be a difficult time on a woman's body. She may experience many noticeable changes in her everyday life, including lower back pain. According to a cross-sectional study of symptoms and signs of pregnant women, though back pain is common in the general population, about 50% of pregnant women experience this discomfort (Sturesson et al., 1997). In this article, the authors use their study to show that lumbar back pain increases in incidence and intensity during pregnancy. To complement these facts, a separate study of two hundred pregnant women were interviewed, finding that 56% of these women experienced lumbar pain (Fast et al., 1987). The results concluded that standing, sitting, forward bending, lifting, and walking tended to increase low-back pain in pregnant women. Yet another study concluded that the weight-bearing stress and tension that a pregnant woman experiences leads to joint instability and a painful lumbar spine (Slatis and Eskola, 1989). Obviously, normal functioning of a woman's body is affected by pregnancy, and our group is very interested in observing this discomfort from a biomechanical point of view. Since there have been a limited number of experiments performed on this topic, we feel that our study will be important to further our knowledge of this phase of life for women.

The purpose of our research is to focus in on one of the most painful changes a pregnant woman may go through &endash; lower back pain. In this study we will analyze the gait pattern of a pregnant woman in her third trimester and a non pregnant woman to see if there are structural differences in their gait patterns leading to lower back discomfort. The way in which we have chosen to address this project is by examining our video footage of the non-pregnant woman and the pregnant woman that we recorded in lab. From the activity of the joint markers placed on the subjects during the filming, we will see that their variant movements may demonstrate the effects of weight and center of gravity on lumbar region discomfort during pregnancy.