Reliability and Validity of Key Performance Metrics of Modified 505 Test.

This study aims to explore the reliability and validity of essential performance metrics derived from a modified 505 Change of Direction (CoD) test. Twenty-seven physically active male participants (age: 18.77 ± 1.73 years) who engaged in three to five training sessions per week were assessed using both standard and modified sprint and CoD protocols. The evaluation focused on sprint time, CoD time, total time, and the Limb Symmetry Index (LSI). The modified protocols demonstrated good reliability for sprint and CoD times (ICC > 0.8, CV < 3%) and high validity, with strong correlations between standard and modified tests for sprint (r = 0.59-0.80) and CoD times (r = 0.58-0.80). The total time metric showed excellent reliability (ICC > 0.9), supporting its utility as a comprehensive measure. Reaction-time inclusion increased variability (CV > 7%) but enhanced ecological validity by reflecting real-world conditions. However, the LSI exhibited lower reliability (ICC < 0.6), indicating the need for further refinement. Combining multiple performance measures, the modified protocols streamlined assessments, reducing fatigue and redundancy without compromising precision. These findings highlight the potential of integrating multidimensional agility metrics in athletic evaluations, bridging the gap between controlled testing and competitive demands. Future research should explore broader populations and sport-specific stimuli to enhance applicability.