This study investigated how different weekly resistance training frequencies affect mechanical output and perceived exertion under velocity loss (VL) monitoring when the total number of sets per week was fixed. Fourteen well-trained male subjects participated in a repeated-measures design in which all participants performed three training frequency conditions (four, three, or two sessions per week) in randomized order. Each condition involved 12 total sets of back squats at 80% one repetition maximum (1RM) with a 20% VL, the total training sets evenly distributed across sessions. The results indicated that increasing training frequency allowed for lower perceived exertion (p = 0.005). Furthermore, the frequency of four sessions per week did not compromise velocity output or repetition performed in the following sets for within-session comparison (p ≥ 0.125), whereas the other two frequencies resulted in compromised performance with increasing numbers of sets performed. The frequency of three sessions per week resulted in a significant decrease in the following set, as shown in the number of repetitions performed per set (N_set) (Δ = 8%,p = 0.003) and the average set mean velocity (MV_average) (Δ = 4%, p = 0.013) in the last set compared with the first set. The frequency of four sessions per week resulted in lower N_set (Δ = 17%), MV_average (Δ = 8%), and fastest mean velocity (Δ = 7%) and last mean velocity (Δ = 9%) of the set in the last set compared with the first set (0.001 ≤ p ≤ 0.033). All training frequencies allowed adequate recovery from the frequency arrangement and did not impact performance in the subsequent session. Overall, under a fixed number of sets performed weekly, increasing training frequency helped preserve velocity output and repetitions performed within-session when using 80% 1RM and 20% VL, while also reducing perceived exertion. It is recommended that athletes distribute strength training more evenly across the week rather than concentrating it into fewer days when pursuing better mechanical output and lower perceived exertion.

• Different training frequencies with a fixed number of weekly sets under velocity loss (VL) monitoring lead to slightly different training results.

• A higher training frequency helps to maintain movement velocity and the number of repetitions performed per set under VL monitoring.

• Spreading the same number of training sets over more training sessions results in less perceived exertion.