Maximal strength assessment, particularly the one-repetition maximum (1RM) test, is essential in resistance training and sports science. Velocity-based metrics like mean concentric velocity (MCV) at 1RM and load-velocity profiling enhance neuromuscular monitoring, yet the stability of parameters such as load-velocity slope (VL-Slope) and peak power position (PP-Position) over repeated tests remains uncertain. Thus, 14 resistance-trained male participants (age: 25.2 ± 3.3 years; training experience: 2.1 ± 2.0 years) performed five 1RM tests in the squat and bench press over a seven-week period. Strength and velocity parameters, including 1RM, MCV at 1RM, VL-Slope, and PP-Position, were assessed using an inertial measurement unit. A repeated-measures ANCOVA was conducted to analyze changes over time, with effect sizes quantified using partial eta squared (ηp²) and standardized mean differences (SMD). No significant training-induced adaptations were observed for 1RM or MCV at 1RM across all testing sessions (p > 0.05). VL-Slope and PP-Position remained stable, indicating no systematic changes over time. However, exercise-specific differences were found, with higher absolute loads and velocities in the squat compared to the bench press. Additionally, PP-Position was significantly higher in the squat, suggesting that peak power output occurs at a higher relative load for lower-body exercises. Repeated 1RM testing does not appear to induce relevant strength or velocity adaptations over time. Coaches and practitioners should consider exercise-specific differences in force-velocity characteristics when designing training programs and interpreting performance diagnostics.