Impact of Prior Fatigue on Velocity Loss as a Set-Termination Criterion in the Bench Press Exercise

This study analyzed the relationship between the percentage of completed repetitions with respect to the maximum that can be performed (%Rep) and the velocity loss (VL) in the bench press exercise after a previous effort (PE). Fourteen men performed four protocols (one week apart) consisting of a set to failure with 60% of one-repetition maximum (1RM) preceded by a PE with the same load but different VL magnitude (0%: PE₀, 20%: PE₂₀, 40%: PE₄₀, and 60% of VL: PE₆₀). Velocity against 60% 1RM (V60-load) and blood lactate concentration were measured after each PE. The relationship %Rep-VL was obtained through the coefficient of determination (R²) and the standard error of estimate (SEE). Absolute reliability and differences during the set to failure were calculated. V60-load decreased significantly in all protocols (except PE₀) (p ≤ 0.05). Blood lactate concentration increased with the magnitude of effort (p ≤ 0.05). Regarding the relationship %Rep-%VL, as the %VL increased during the PE, the R² decreased and the SEE increased. %Rep showed "satisfactory" absolute reliability above 15%VL, with the absolute differences being high-moderate (<10%) for all VL magnitudes (except PE_0-40 with 60%VL). VL is a reliable and accurate set termination criterion with a PE of any magnitude, but higher reliability is observed with low-moderate levels of fatigue.