The goal of this study was to determine the accuracy of the Scale of Perceived Exertion (RPE) OMNI RES 0-10 and the Linear Velocity (V) to predict the 1RM value in two resistance training exercises: Bench Press (BP) and Parallel Squat (PS), in a group of young baseball players. 32 young men baseball players (15.6+0.7 yr) performed a progressive test (PRT) in BP and PS with incremental load until reach the maximum load that can be mobilized (1 RM). The RPE OMNI-RES 0-10 Scale was used to assess the effort's perception experimented at the end of the PRT set and a rotating encoder was used to get the average lineal velocity reached with each load. Two lineal regression analyses where made to predict the 1 RM percentages and calculate the 1 RM. 1) One between theV (as independent variable) and % 1 RM (as dependent variable) 2) The other one between the RPE (as independent variable) and % 1 RM (as dependent variable). The averaged 1 RM achieved were 66.8±12.8 and 153.8±22.6 for BP and PS respectively. The 1 RM prediction models were statistically significant (p < 0.01) for either velocity(r = 0.97 SEE% 12.2 and r = 0.93 SEE 14.6%) or RPE(r = 0.90SEE% 6.4% and r = 0.97 SEE% 6.7%) for BP or PS respectively. The regression equation developed for each model were: 1 RM BP = 100 × kg/(1.050 + (−0.517)v) and 1 MR BP = 100 × kg/(0.266 + 0.075(RPE)); 1 RM PS = 100 × kg / ((1.094 + (−0.388) v) and 1 RM PS = 100 × kg / (0.572 + 0.043(RPE)).The covaried analysis showed significant differences (p < 0.05) between the regression RPE-%1RM regression line developed for BP and PS, but not for the two BP or PS v-%1 RM regression. For both exercises (BP and PS), we can estimate the 1 RM value from the velocity or the RPE determined during or at the end of a short set of only 1 to 3 rep with a submaximal load mobilized with the maximal possible velocity. These equations allow a continuous control of the strength evolutions during the training process, although when the V is utilized as the predictive variable we can assign the same equation for BP or PS, but when you uses the RPE we have to develop a specific equation for each different exercise. Furthermore, from the SEE% the RPE equation shows a more accurate value than the V equation.