USABILITY OF ISOTONIC DYNAMOMETRY TESTING IN CHILDREN AND YOUTH

This study aims to investigate the usability of isotonic dynamometry in children and youth by determining the correlation between isometric dynamometry, which is considered the most valid direct-laboratory method for the assessment of muscle contractile properties in children, and isotonic dynamometry. The sample of the participants was composed of children and youth aged 7 to 19 years divided into 3 groups: younger school age (7-10 y), middle school age (11-14 y) and high school age (15-19 y). Implemented tests were the hand grip strength test (isometric dynamometry) and countermovement jump on the force plates (isotonic dynamometry). The results of Pearson’s correlation coefficient revealed that there is no significant correlation between Fmax, RFD and jump height in younger (r = 0.176, p = 0.291; r = 0.152, p = 0.363, respectively) and middle school-age children (r = 0.059, p = 0.733; r = 0.201, p = 0.241, respectively) while there is a high correlation in the group of high school participants (r = 0.531, p = 0.001; r = 0.544, p = 0.001, respectively). This study's results indicate that the isotonic dynamometry method is not valid for implementation in the group of children under the age of 15.