Gender specific lumbar range of motion and its association with trunk and hip muscle strength and flexibility stratified by body mass index in healthy adults / Nur Aainaa Mohd Rasid

A sufficient range of motion of lumbar is essential for various activities in our daily lives. In facts, muscle strength and flexibility as well as body mass index (BMI) may influence lumbar mobility of an adult. Thus, this study investigated associations between variables of range of motion (ROM), trunk and hip muscle strength and flexibility stratified using BMI by gender among healthy adults. One hundred and seventy-six participants (102 females and 74 males of 20 to 40 years of age) were tested for lumbar ROM (flexion, extension, rotation and lateral flexion) using back range of motion. For trunk and hip extensor strength the push- pull dynamometer was used while for the hamstring and hip flexor flexibility the sit and reach and modified Thomas test was applied. Significant correlations were observed between lumbar lateral flexion and trunk muscle strength in overweight/obese female participants (p<0.05, r=0.35), lumbar rotation and hip extensor strength in normal weight (p<0.05, r=0.314) female participants. There were correlations between lumbar rotation and lateral flexion and hamstring flexibility in overweight/obese (r=0.308, p<0.05) and normal weight (r=0.492, p<0.05) in male participants, respectively. Regression analysis revealed that trunk muscle strength significantly associated with lumbar lateral flexion for overweight/obese female participants (R² = 0.122) and hamstring flexibility were associated with rotation for overweight/obese in male participants (R² = 0.136). As a conclusion, the study results suggest that trunk extensor muscle strength and hamstring muscle flexibility should be addressed together with lumbar lateral flexion in overweight/obese females and the lumbar rotation in overweight/obese males.