This systematic review examines the physical performance determinants of youth swimmers, focusing on strength, power, anaerobic and aerobic measures, and body composition. The review included 43 studies that met the inclusion criteria, with a total of 1837 participants. The studies used various methods to assess swimming performance, including time trials, event results, and physiological parameters such as VO2, blood lactate (BL), and body composition. Key findings indicate that greater muscle strength, muscle power, lean body mass (LBM), and anaerobic and aerobic capacities are associated with superior swimming performance. Body fat percentage (BF%) has a more nuanced relationship with swimming performance, with some studies showing a positive correlation and others finding no significant relationship. The review also highlights the importance of general strength and power training in enhancing swimming performance, particularly for start and turn performance. Anaerobic power is crucial for sprinting, while aerobic capabilities are more important for longer events. LBM is beneficial for both genders, likely due to its association with strength and power. However, the relationship between BF% and swimming performance is uncertain, and further research is needed to clarify this relationship. The review suggests that coaches should prioritize strength and power training, along with anaerobic and aerobic training, to enhance swimming performance in youth swimmers. The findings provide a better understanding of the physiological and anthropometric factors influencing youth swimming performance, offering insights for future research and training programs.This systematic review examines the physical performance determinants of youth swimmers, focusing on strength, power, anaerobic and aerobic measures, and body composition. The review included 43 studies that met the inclusion criteria, with a total of 1837 participants. The studies used various methods to assess swimming performance, including time trials, event results, and physiological parameters such as VO2, blood lactate (BL), and body composition. Key findings indicate that greater muscle strength, muscle power, lean body mass (LBM), and anaerobic and aerobic capacities are associated with superior swimming performance. Body fat percentage (BF%) has a more nuanced relationship with swimming performance, with some studies showing a positive correlation and others finding no significant relationship. The review also highlights the importance of general strength and power training in enhancing swimming performance, particularly for start and turn performance. Anaerobic power is crucial for sprinting, while aerobic capabilities are more important for longer events. LBM is beneficial for both genders, likely due to its association with strength and power. However, the relationship between BF% and swimming performance is uncertain, and further research is needed to clarify this relationship. The review suggests that coaches should prioritize strength and power training, along with anaerobic and aerobic training, to enhance swimming performance in youth swimmers. The findings provide a better understanding of the physiological and anthropometric factors influencing youth swimming performance, offering insights for future research and training programs.