The purpose of this study was to investigate the effects of Swiss ball training on (1) knee joint reposition sense (knee proprioception), (2) core muscle strength and (3) dynamic balance in sedentary collegiate students. In this thesis, two different participant groups and two different training methods were used. In order to evaluate the effect of Swiss ball training on knee proprioception and core strength, 3 days per week training was conducted throughout 10 weeks (Study 1). In order to evaluate the effect of Swiss ball training on dynamic balance, 2 days per week training was conducted throughout 10 weeks (Study 2). 60 sedentary university students participated in Study 1. 47 sedentary university students participated in Study 2. The results of the study indicated that Swiss ball training has significant effect on knee proprioception and core muscle strength. For dynamic balance, at the end of the 10-week Swiss ball training, in both groups (Swiss ball and control), dynamic balance scores were improved significantly. Therefore, effect of the Swiss ball training on dynamic balance could not be determined. As a conclusion, an instability training program using Swiss balls with body weight as resistance can provide prolonged improvements in joint proprioception and core strength which would contribute to general health and performance.