This study, it was aimed to examine the effect of athletes' mental toughness levels on athlete engagement and exercise addiction levels. The study group of the research consisted of athletes engaged in defense (combat) sports in 2023. In the study, the Athlete Engagement Scale (AES) developed by Lonsdale, Hodge and Jackson (2007) and adapted into Turkish by Kelecek, Kara and Aşçı (2017), the "Mental Toughness Inventory in Sports" (MTIS-14) developed by Sheard et al. (2009) and adapted into Turkish by Altıntaş (2015), and the Exercise Addiction Scale for Young People developed by Lichtenstein et al. (2018) and adapted into Turkish by Dokuzoğlu et al. (2022) were used as data collection tools. SPSS 25.00 package program was used for data analysis. Whether the data were normally distributed or not was decided based on the skewness and kurtosis values between ±2 (Shao, 2002). Statistically, Pearson correlation analysis, linear regression analysis, frequency, percentage and reliability coefficient calculations were used. As a result of the research, it was determined that mental toughness has a significant effect on athlete Engagement and exercise addiction.

Commitment, Exercise Addiction, Mental Endurance, Defense Sports.