Movements in the frontal plane, such as accelerations, cutting, and kicking, are common in soccer. This abstract focuses on isometric strength testing of hip adductors and abductors and its relationship to athletic performance and soccer-specific training. The first study evaluates the test-retest reliability of handheld dynamometry in measuring hip adductor and abductor isometric strength using various positions and fixation methods in females. The results demonstrate good reliability under all conditions, with the standing position without belt fixation being the most optimal for assessments. These findings provide guidance for clinicians and researchers in selecting the best conditions for frontal plane isometric hip strength assessments. The second study investigates variations in isometric frontal plane hip strength in female collegiate soccer players before and after a high-workload soccer-specific training session. The results show significant decreases in hip adduction and abduction following the intense training session, highlighting the impact of high workloads on isometric hip adductor and abductor strength. Furthermore, the study reveals correlations between changes in hip strength and distance covered at high speeds, emphasizing the importance of monitoring hip strength and its changes in relation to internal and external training load. The third study examines seasonal fluctuations in isometric hip adductor and abductor strength among collegiate female soccer players. Variations in hip strength are observed throughout the competitive season, with the highest values recorded in the post-season. However, no significant correlations are found between hip adductor and abductor strength and internal/external training load. The findings highlight the need for adjusting and individualizing training and recovery sessions to optimize performance and reduce injury risk in collegiate female soccer players. In summary, these studies underscore the importance of monitoring and optimizing hip adductor and abductor strength in soccer players to enhance performance and minimize injury risk. The findings provide valuable insights for clinicians and researchers in assessing and training frontal plane hip strength in soccer players.