Desenvolvimento, confiabilidade e validação de um protótipo de monitoramento da velocidade da bola de futebol de campo

Abstract

The need for more efficient tactical-technical training has become a continuous search for high-level athletes, and the development of technology is an indispensable tool for extracting information and measuring progress. Thus, the objective of this study was to develop and analyze the reliability and validity of a prototype that monitors the speed of a soccer ball. This prototype sends information from the athletes' kicks to a mobile device via bluetooth technology. To analyze the test-retest reliability for the speed measurement in the X, Y and Z axis of the accelerometer and the speed measurements by the prototype, the intraclass correlation coefficient (ICC) was used. The results showed consistent ICC values for the variables Z-axis (0.792; p< 0.001); Y-axis (0.863; p< 0.001); X-axis (0.769; p< 0.001). Consistent ICC values were found for the ball speed recorded by the prototype between test-retest sessions (0.818; p< 0.001). There was no significant difference for the ball speed measurement recorded between the prototype vs. bushnell radar (p= 0.232). In the Bland Altman analysis, the bias was observed to be 0.16 ± 0.9 Km/h; Upper bound of agreement= 2.05; Lower bound of agreement= -1.73. The simple linear regression test showed that there was no error of proportion bias (r2= 0.385). The intraclass correlation coefficient showed a high reliability between the ball speed recorded by the prototype compared to the radar gun (ICC = 0.81; CI= 0.71 - 0.91; Cronbach's alpha= 0.809). It is concluded that the monitoring prototype developed in the study is valid and reliable for measuring field soccer ball speed.