Abstract
Power is essential in sports and is typically calculated using a standard gravity value of g = 9.81 m·s(-2). However, this value varies according to altitude and geographical latitude. The aim of this study was to improve the accuracy of power calculations using a photoelectric cell system and the local g value. First, the uncertainty in jump power calculation induced by the direct measurements involved in its estimation was analyzed in this cross-sectional study. Subsequently, the power values obtained for ten volleyball players were calculated through repeated jump tests of 15, 30, and 60 s, using a kinematic system composed of a transmitting bar and a receiving bar with 96 infrared LEDs that detect flight and ground times for each jump. The local gravity values for 34 different locations-obtained through the Geodetic Reference System, taking into account the altitude of each location-and the standard value of g = 9.81 m·s(-2) were used for the power calculation. Significant differences were observed, with underestimation occurring at higher altitude locations and overestimation at lower altitudes. To conclude, the results indicated that the geographic location of the experiment should be considered, and the use of GRS80 local gravity values is recommended to improve the accuracy of jump power calculations.