Original articles
Changes and relationship among low back pain, gait index, and physical activity during pregnancy
2020 Volume 34 Issue 1 Pages 3-13
Details
2020 Volume 34 Issue 1 Pages 3-13
Purpose
The purpose of this study was to 1) examine changes in low back pain, gait index (visualization index of gait and step according to kinematic data), and physical activity in the second and third trimesters of pregnancy: and 2) determine the relationship between these three variables.
Methods
The study participants were 35 Japanese pregnant women. Clinical data on low back pain, gait index, and physical activity were collected twice, once during the second and once during the third trimester. The visual analog scale (VAS) was used to measure low back pain. Gait measurements were recorded using a wireless motion recording sensor unit containing a piezoresistive triaxial accelerometer and a triaxial gyroscope. For gait analyses, we calculated the coefficient of variation (CV), root mean square (RMS), harmonic ratio (HR), and autocorrelation coefficient (AC). RMS, HR, and AC were measured across three physical planes: vertical (VT), mediolateral (ML), and anteroposterior (AP). Physical activity was measured by wearing a life coder GS® for three or more days.
Result
Eighteen pregnant women (51.4%) with no back pain before pregnancy had higher VAS during the third trimester than in the second trimester (p=0.01). Steps (p=0.01) and medium/high intensity activity time (p=0.01) decreased significantly more in the third trimester than in the second trimester. CV was significantly larger during the third trimester than during the second trimester (p=0.03). The third trimester showed a significantly smaller RMS in the mediolateral planes than did the second trimester (p=0.03), which showed trunk stiffness. A moderate negative correlation was observed between HR in the second trimester and VAS in the third trimester (r value: −0.411 to −0.517, p<0.05). Moderate positive correlations were observed between number of steps/day in the second trimester and RMS (r value: 0.436，p<0.05) and AC in the third trimester (r value: 0.379 to 0.460, p<0.05).
Conclusions
This study found that gait indices were more unstable in the third trimester than in the second trimester. Pregnant women were able to maintain their gait ability by reducing their body sway due to muscle depression. Unstable gait indices may lead to increased falls, so supported exercise regimes are required to ensure and maintain gait stability from the second trimester until the third trimester.
