The purpose of the study was to find out the relationship among coaching knowledge, trust on coach, and sport behavior of Judo athletes. The study involved players in secondary school who have been registered by the Korean Olympic Committee in 2015. 320 Judo athletes were selected from this population using the cluster sampling method. This study included 292 valid sample questionnaires in total. The study used coaching knowledge, trust on coach, and sport behavior as factors of measurement. Data were collected through the questionnaire using the concept re-organized by Chung Ji Hye, and Huh Jung Hoon(2006) to verify coaching knowledge. Also, this study used the questionnaire from Nam Kwang Woo, and Cho Ook Sang(2014) to verify trust on coach, and used the questionnaire from Kim Jung Wan, and Kim Jung Nam(2002) to verify sport behavior. For this study, collected data were analyzed by using SPSS 21.0 version of windows. First of all, a frequency analysis was conducted and to assess the validity of the demographic characteristics of subjects. And this study was also conducted by a factor analytic investigation and reliability analysis to look into internal consistency. To analyze the differences among the factors according to background variables, this study was performed by descriptive statistics analysis, t-test, and one-way ANOVA. Lastly, this study utilized a correlation analysis and standard multiple regression analysis to analyze the relationship among coaching knowledge, trust on coach, and sport behavior of Judo athletes.

The conclusions are as follows,
First, there is a significant difference between trust on coach and general sport behavior characteristics of the subjects. To explain more specifically, according to sex, male players perceived calculus-based, knowledge-based and identification-based trust, which are subordinate factors of trust on coach, more highly than female players. Also, depending on motivation of exercise, middle school players perceived behavior of teammates higher than high school players.

Second, coaching knowledge which is perceived by players had a significant effect on trust. Knowledge of training method and understanding players had an impact on entire subordinate factor of trust on coach. Also, this study revealed that knowledge of coaching theory had an effect on calculus-based trust. Knowledge of training process had an effect on calculus-based trust and identification-based trust. And knowledge of competition strategies had an effect on knowledge-based trust and identification-based trust

Third, coaching knowledge which is perceived by players had a significant effect on sport behavior. Knowledge of training method and competition strategies had an impact on all subordinate factor of sport behavior. Also, knowledge of coaching theory had an effect on involvement of sports behavior and knowledge of understanding players had an effect on performance of sports behavior.

Forth, trust on coach which is perceived by players had a significant effect on sport behavior. Calculus-based trust and identification-based trust which are the subordinate factors of trust on coach had an effect on entire subordinate factors of sports behavior. Furthermore, Calculus-based trust and knowledge-based trust had an effect on the motivation and performance of sport behavior.