Adam Leja, Jordan Glenn, Ludmila Cosio-Lima, and Bhargav Desai University of West Florida, Pensacola, FL 32514 Research has been conducted to confirm the idea that the rectus abdominus is affected by training on an unstable surface (Cosio-Lima, et al., 2003), but research involving upper and lower body is scarce. Therefore, the purpose of this study is to investigate the effects of a training program on the BOSU Ball on muscles of the upper and lower body. METHODS: Sixteen collegiate students (8 males and 8 females age21.9 ± 3.1 years) from the University of West Florida with no background experience using a BOSU Ball participated in the study. Subjects performed 3 sets of 5 pushups on and off a BOSU Ball achieving90 degree elbow flexion and 3 sets of 5 squats achieving 90 degree knee flexion. There was no rest period in between each exercise and sets were alternated until all repetitions were fully completed. Statistical significance was set at (P< 0.05). Data was analyzed using repeated measures ANOVA (SPSS 17). RESULTS: Rectus abdominus activation increased significantly (P= 0.013) when the BOSU ball was introduced for the purpose of the push-up exercise. Additionally, there was a significant increase (P= 0.040) in mean triceps brachii activation the unstable surface (317.8 mV ±SD) of the BOSU ball vs. mean triceps activity on the stable surface floor (272.6 mV ± SD) during the push-up exercise.Moreover there was a significant increase (P = 0.047) seen in rectus abdominus activity during the squat exercise on the BOSU ball vs. the floor. No significant difference was found (P > 0.05) in the pectoralis major activity during the push-up exercise. CONCLUSIONS: The present study demonstrates the implementation of a BOSU ball will elicit a significant increase in rectus abdominus and triceps brachii activation during a push-up as well as an increase in rectus abdominus activation during a squat exercise. The prescription of unstable surface training may be beneficial when attempting to increase muscle proprioception.