ESTIMATING FLIGHT TIME AND VERTICAL ONE-LEGGED JUMPING HEIGHT IN ELITE UNDER-20 SOCCER PLAYERS

The evaluation and analysis of the vertical jump are regular in the follow-up processes in sports performance and the rehabilitation of athletes. These assessments are conducted in laboratory environments and using expensive and complex technologies that require evaluators' expertise. Recently, the My Jump 2 mobile application proved its validity compared to force plates in the two- legged vertical jump. However, the validity of this mobile application for estimating the values of the SJ (Squat Jump) and CMJ (Countermovement Jump) one-legged jump variants in soccer players is still being determined. Twenty-four elite under-20 soccer players participated in this study. They were assessed simultaneously with the OptoGait device and the My Jump2 application following the SJ and the CMJ one- legged variant protocol. There was an excellent agreement between My Jump 2 and OptoGait, both SJ and CMJ one-legged jump for flight time and jump height (intraclass correlation coefficient = 0.902-0.929, p < 0.05; Bland-Altman bias = % difference 7-15). Good repeatability and reproducibility were established for the same variables in both the right and left lower limb between evaluators (intraclass correlation coefficient = 0.591- 0.835, p < 0.05; variation coefficient percentage = 2.87 to 10.72). The results suggest that the My Jump2 application is a practical, costeffective, and valid instrument for the assessment of jumping in young elite soccer players, as well as a portable alternative of easy operation in the field for the use of professionals in Sports Science and Physiotherapy.