Objectives: Aging and change in the skeletal muscle are certain challenges faced by the elderly. This condition leads to a decrease in the musculoskeletal functions, physical function, and disability compared to the younger individuals. Thus, the current study aimed at examining the exercise of back stabilizer muscles of aged women compared to the young ones in response to resistance training and soy milk supplementation. 
Methods & Materials: The study had a quasi-experimental design conducted on 27 old women (Mean [SD] age: 69.60[3.16] years) and 10 young ones. The aged women were randomly divided into back stabilizer exercise plus soy milk, back stabilizer exercise, and control groups (9 subjects in each group). They took part in exercise-nutrition interventions for 10 weeks, 3 sessions per week. The subjects were given soy milk to drink three times in a day with and without exercise. Ultrasonic features of multifidus, ability, back performance, and nutrition status of aged women were measured pre- and post-intervention. Data were analyzed by 2-way ANOVA. 
Results: Mean (SD) multifidus cross-sectional area of aged women (3.49[0.908] cm2) was significantly smaller than that of young ones (7.42[1.52] cm2) during pre-intervention. Following the intervention, it significantly increased in both stabilizer exercise plus soy milk and back stabilizer exercise groups (P<0.05, 5.41[0.44] and 5.28[1.18] cm2, respectively), but did not completely modify. Ability and back performance of intervention groups showed significant development compared to control group (P<0.05, -10.2[3.3] and -11.72[2.8] cm2, respectively). 
Conclusion: Ten weeks of stabilizer exercise and consuming soy milk led to an increase in the ultrasonic features of back multifidus muscle of aged women and decreased the age-related muscle changes. On the other hand, improvement in multifidus muscles not only resulted in ability and back performance promotion, but also led to independency and social activity development in the aged women.