KNEE BIOMECHANICS IN OBESE FEMALE DURING LOCOMOTION

Abstract

The obese woman is strongly knee ostroarthritis 'at risk' group. The high BMI is knee ostroarthritis risk factor by biomechanics during locomotion. The purpose of this study were to compare knee biomechanics during walking such as gait tempero-spatial, kinematic, and kinetic (external knee adduction moment) between overweight obesity I, obesity II and normal healthy female subjects, to study the correlation between gait tempero-spatial data, kinetic and kinematic data (external knee adduction moment), and anthropometry and female BMI levels, and to assess the biomechanical effectiveness of the lateral wedge insole among normal, overweight, obesity I and obesity II females when walking. Eighty Thai females aged between 18 to 40 years, participated in this study and categorized into 4 groups such as normal, overweight, obesity I and obesity II by BMI level (WPRO). A cross-over randomized study was designed to investigate each walking velocities such as self selected, constant velocity (1.24 m/s), and Frode velocity of all participants using 3-D Motion Analysis (N = 80). The significant difference was determined using 2-way ANOVA (p = 0.05) and the correlation of anthropometrics, biomechanics parameter and BMI were determined by Pearson correlation test in study 1. In study 2, the significant difference was determined using Repeated-ANOVA (p = 0.05). The results of study 1 indicated that the overweight and obese groups had changed gait biomechanics and increased knee joint load during walking in all type of velocities when compared with normal groups. The dynamic stability of obese group was maintained by wider step width, longer stance phase duration, shorter swing phase and higher double support time. The BMI was significantly correlated with step width, support time, non support time, double support time and peak external knee adduction moment in low level. The results of study 2 indicated that the peak external knee adduction moment was decreased by the effect of walking shoes and walking shoes with lateral wedge insoles in the self selected speed walking condition. However, the peak external knee adduction moment did not change in the obesity II group. Additionally, there was no effect of lateral wedge insoles on knee adduction angular impulse in all groups during walking. In conclusion, the knee adduction moment was higher in overweight, and obese participants that represent the higher knee joint load to be induced joint cartilage damage cause of osteoarthritis. However, the lateral wedge insoles did not provide any knee joint load effect in the obesity II group. For future study, using the orthosis for reduce biomechanical load that cause of joint cartilage may interest to investigate for prevention potential knee joint osteoarthritis in high BMI female person. In addition, using of lateral wedge insole should be concerned to investigate the long term effect and length of time to apply lateral wedge insoles among those of higher BMI levels, such as obesity II individuals.