Purpose The purpose of this study was to identify the effect of a power-specific weight training program in order to improve the muscle strength of Korean national team’s freestyle wrestlers. Methods Participants were 13 male athletes in the national freestyle wrestling team. The period of the program was 6 weeks. Muscle strength, muscular endurance, muscle power, flexibility, agility, cardiorespiratory endurance, anaerobic power and isokinetic muscle function were measured. Data were analyzed using IBM SPSS Statistics ver. 23.0 (IBM Co., Armonk, NY, USA). Paired t-test was conducted for comparison between pre-test and post-test score. Results There were significant difference and tendency in the leg isokinetic power and trunk isokinetic flexion strength. However, there was no significant difference in muscle strength, muscular endurance, muscle power, flexibility, agility and cardiorespiratory endurance. Conclusion The 6-week program focusing on the power-specific weight training indicated a significant difference not in every variable but in isokinetic muscle power, speed power and core strength. It is suggested that the training program was applied to the athletes less continuously and not in the long term because of frequent international games abroad and the need for losing weight. Consequently, a year-long training program with personalized methods should be developed to bring about more significant outcomes.