Relationship Between Kinetic Variables of Isometric Knee Extension Test with Vertical Jump Test

Purpose: To determine the level of correlation between isometric knee extension (IKE) tests in isokinetic dynamometer and vertical jump test in portable force platforms. Methods: Twenty-eight adult males performed the IKE at two angles (60 degrees and 75 degrees) and the squat jump test (SJ). For the SJ, the following variables were calculated: peak force; rate of force development (RFD) in intervals every 50 ms; peak RFD (PRFD) and jump height were calculated using the flight time (JHFT) and the impulse method (JHIM). For the IKE, the following variables were calculated: peak torque; rate of torque development (RTD) in interval of 50 ms; and peak RTD (PRTD). Pearson s correlation coefficient was used. Results: Trivial to moderate correlations were found between the SJ and IKE variables. In 60 degrees knee angle IKE, JHFT have moderate correlation with PRTD and RTD50 (r = 0.51; p = 0.01 and r = 0.49; p = 0.01 respectively). In 75 degrees knee angle, PF have a weak correlation with PT (r = 0.37 and p = 0.05) and moderate with RTD100 (r = 0.46 and p = 0.02), RFD50 have moderate correlation with PRTD and RTD50 (r = 0.53 and p < 0.01 in both), and RFD100 have moderate correlation with PT (r = 0.40 and p = 0.03). Conclusion: It is concluded that the kinetic variables of the IKE test have a trivial to moderate effect on SJ variables, so the variables of SJ could not be considered interchangeably with those of IKE.