Introduction: Associated with obesity, weight loss has increased significantly during the past two decades, which is still one of the most common disorders. The aim of this study was to investigate the effect of 4 weeks of resistance training combined with alfalfa extract on cathepsin S and cystatin C in weight loosed Girls.

Materials & methods: This study was conducted on 28 adolescent girls with weight loss. They were randomly divided into four groups (each group,n = 7): exercise, exercise-supplement, control, control –supplement.Resistance exercise training protocol consisted of 4 weeks and 3 days a week with 60% of one repetition maximum (1RM) at the beginning and 80% of 1RM at the end. Supplement groups consumed alfalfa extract1 cc (per kg body weight) and blood samples were taken before and after 4 weeks of the study.

Findings: After 4 weeks concentrations of cathepsin S and cyctatinC in exercise group exercise–supplement and Control-Supplement was significantly reduced (p<0.05). But in control group there was no significant decrease (p<0.2).

Discussion & Conclusions: This study showed that 4 weeks of resistance training combined with alfalfa extract increased weight, decreased levels of cathepsin S and cyctatin C, which resulted in body composition improvement.