Curve Sprint Ability as an Indicator of Neuromuscular Function and Physical Fitness in Youth Soccer Players: Comparative Insights from U14 and U16 Groups

<i>Background and Objectives</i>: In modern soccer, players frequently perform curved sprinting (CS) actions that combine speed, agility, and neuromuscular control, highlighting the importance of assessing CS performance in youth athletes. This study aimed to investigate age-related differences in CS performance and its relationship with key components of physical fitness-including aerobic capacity, vertical jump height, and agility-based field tests-in U14 and U16 male soccer players. <i>Materials and Methods</i>: A total of 76 registered players participated, evenly divided between the two age groups. Statistical analyses included t-tests, correlation, and regression modeling to determine key predictors of curve-sprint performance. <i>Results</i>: U16 players showed significant between-group differences, with faster CS times on both the good and weak sides (<i>p</i> < 0.001, d = 0.93-1.08), as well as superior performance in the countermovement jump (<i>p</i> < 0.001, d = 1.12), Illinois Agility Test (<i>p</i> < 0.01, d = 0.70), and 5-0-5 change-of-direction (COD) test (<i>p</i> < 0.01, d = 0.74). Significant negative correlations were found between CMJ height and CS times (r = -0.40 to -0.73), indicating that greater explosive power was associated with better CS performance. Moderate to very strong positive correlations were observed between CS and agility measures (r = 0.43 to 0.79), particularly in the U16 group, whereas VO₂max showed no meaningful relationship with CS performance (r = -0.16 to -0.30, <i>p</i> > 0.05). <i>Conclusions</i>: These results suggest that CS may serve as an indicator of neuromuscular power and agility, both of which improve with age. From a practical perspective, regular curve-sprint assessments and multidirectional drills may support talent development by helping coaches monitor neuromuscular efficiency and movement coordination in young players.