The aim of this study was to analyze the relationship between two methods of measuring of extensor muscle dynamic force in the inferior limb by means of isokinetic dynamometry and a contact platform system. Twenty‐four members of the junior and senior National Spanish teams for alpine skiing and high jump and track and field athletics participated in the study. The isokinetic dynamometry parameters studied were: peak torque (PT) at five different angular velocities, and total work accomplished in 20 repetitions of maximal intensity effort at an angular velocity of 300°.s‐1(R20). Vertical jump height (SJ) was measured by a contact platform device. The correlation between PT and the vertical jump test was significant p<0.005). The strongest correlation was observed between PT 120°and PT 240°with SJ 20 (r = 0.81; p<0.001). We conclude that both methods may be used satisfactorily to measure the dynamic force of knee extensors muscles. The difference observed between methods may be discussed in terms of the relative utilization of the elastic and reactive components of dynamic force, the participation of other muscular groups in the movement, and other characteristics of ballistic movement.