Training at a specific movement tempo is a relatively new concept in resistance training. It is based on manipulation of the duration of particular phases of a movement. General studies have demonstrated that faster movement tempo in resistance training leads to an increase in muscle power, whereas lower movement speed is beneficial in the development of muscle strength and hypertrophy. However, the studies in this area are inconclusive and do not relate precisely to various tempos and movement speeds. The aim of the study was to determine the effect of duration of the eccentric cadence ECC_REG (2/0/X/0) and ECC_SLO (6/0/X/0) on muscular power generated in the concentric phase of the movement expressed in maximal P_MAX, V_MAX and average values P_AVE, V_AVE. For the ECC_SLO (6/0/X/0) cadence, a significantly lower value of P (401.95 ± 65.42 W) was observed compared to the ECC_REG 2/0/X/0 tempo (467.65 ± 79.18 W), at p = 0.007. The same was true for power evaluated in maximal values (P_MAX), as significantly higher values were recorded for the regular ECC_REG (2/0/X/0) (671.55 ± 115.79 W) compared to the slow tempo ECC_SLO (6/0/X/0) (565,70 ± 117,37 W), at the level of significance of p = 0.007. The velocity evaluated for ECC_REG (2/0/X/0) tempo expressed in average values (V_AVE) 0.60±0.09 m/s was significantly higher compared to the ECC_SLO (6/0/X/0) tempo (0.52 ± 0.08 m/s), with p=0.004. When maximal velocity (V_MAX), was considered higher values for ECC_REG (2/0/X/0) tempo was registered (0.79 ± 0.10 m/s) compared to the ECC_SLO (6/0/X/0) tempo (0.69 ± 0.13 m/s), at significance of p = 0.001. The main finding of the study indicates that the duration of the eccentric phase of the movement has a significant impact on muscular power and velocity during the concentric phase of the movement.