The purpose of this study was to investigate the effects of using upper (Bench press) and lower body (Leg curl) exercise during rest interval on rating of perceived exertion (RPE), lactate production and quantity of lower body performance (Leg extension) with 75% 1RM (repetition maximum). 15 resistance trained men (age 20.9±1.9 years, height 175.6 ±4.5 cm and weight 74.8±5.2 kg) took part in four testing sessions with 48 hours recovery between sessions voluntarily. subjects completed randomly exercises during per session one models of leg extension exercise with inactive rest (L1), leg extension exercise with bench press and inactive rest (L2), and leg extension movement with leg curl and inactive rest of 3 min (L3) up to voluntary exhaustion. RPE and Lactate were measured before and after different exercises. For statistical analysis of data, two-way repeated measures and LSD post hoc tests were used. The result showed that all of three exercise models reduced the repetitions in continuous sets specially L2 model, and there were significant differences between sets (P<0.05). Also, there was significant difference between sustainability of repetitions in L2, L3 and L1, L3 exercise models (P<0.05). Also, there was significant difference between lactate production in L2, L3 and L1, L3 and RPE in all exercise models specially L2 model as positive difference (P<0.05). Therefore, it seems that use of combined exercise models, specially combined lower and upper body exercise, not only reduced all times of workout, but also attenuates rating of perceived exertion and lactate production, and maintains quantity of repetitions.