摘要：Background and Study Aim: Resistance exercises under unstable conditions have gained popularity among athletes. The aim of the study was to investigate the changes in muscular outputs (peak power and velocity of movement) during bench presses and squats under unstable conditions in comparison to the outputs under stable conditions. Material and Methods: A total of 20 participants, divided into two groups, took part in the study. The first group consisted of 9 top-level young male judoists, while the second group consisted of 11 students. All of the exercises were performed once 70% of one-repetition maximum (1RM) was determined. Results: The analysis showed a significant reduction in muscular outputs during squats under unstable conditions (the BOSU ball) in comparison to stable conditions for the group of judoists. However, there was no significant reduction in muscular outputs during the bench presses under unstable conditions (the Swiss ball) compared to the stable flat bench. For the group of students, the analysis showed a significant reduction in muscular outputs during the bench press under unstable conditions when compared to the stable flat bench. In addition, for this group the muscular outputs were significantly lower during squats under unstable in comparison to stable conditions. Conclusions: The bench press as a resistance exercise performed on a Swiss ball with reduced training load cannot be recommended as an effective training model for judoists. Nevertheless, the squat with reduced training load under unstable conditions provided sufficient challenges to the neuromuscular system and could be incorporated into training programs
