A study was conducted to explore the utilization of effective social support to prevent athlete burnout. First, 76 varsity-athlete freshmen who belonged to 4 different clubs answered a questionnaire composed of the Athletic Social Support Scale (ASSS; Tsuchiya & Nakagomi, 1994), Athletic Burnout Inventory (ABI; Kishi et al., 1989) and Network Map, which is a modification of the Psychological Distance Map (Wapner, 1978), and they also described their perceived stress by the free description method. We carried out 4 measurements after the subjects had started club activities; one week later (1W), two months late (2M), four months later (4M) and six months later (6M). Secondly, eight of the study freshmen were interviewed during the investigation (60 min×4 lessions). The main results obtained were as follows; 1) The freshmen encountered 3 different types of stress, which were characterized by their transition period. The first type of stress, termed "confusion about athletic life" was experienced more frequently in 1W, the second type, termed "unease about performance enhancement", occurred in 4M, and the third type, termed "complicated relationships with others", occured in 6M. 2) The althletes' perceived stress and burnout tendencies were significantly correlated, and both uncreased throughout the study period. However, the burnout tendency of freshmen with good social support was arrested, whereas that of freshmen with poor social support increased significantly after 2M. Furthermore, path analysis of a longitudinal model for social support and athlete burnout showed that a supportive environment for freshmen at the beginning of their activities was critical for mitigating the stress-burnout relationship. 3) Effective social support for these three types of stress were observed throughout the case study, and identified by multiple regressio n analysis. It is suggested that instrumental support from seniors in 1W, esteem and companionship support from teammates and new friends in 2M, instructive support from coaches and trainers in 4M, and esteem support from seniors and teammates in 6M could buffer the negative effect of stress. Future work should expand these findings into an educational intervention program for freshmen.