Exercise type, training load, velocity loss threshold, and sets affect the relationship between lifting velocity and perceived repetitions in reserve in strength-trained individuals.

Purpose: To explore the relationship between bar velocity and perceived repetitions in reserve (pRIR) for the bench press and the squat exercises during multiple training sessions in strength-trained individuals. Methods: Nineteen well-trained individuals (9♀ and 10♂, 26 ± 4 yr, 174 ± 8 cm, 74 ± 9 kg (mean ± standard deviation)) trained squats and bench press for six weeks. Within each week, they conducted three sessions with different loads, corresponding to ∼77-79%, ∼82-84%, and ∼87-89% of one repetition maximum (1RM). The mean velocity was measured at the bar for all lifts, and the participants terminated each set based on a pre-set velocity loss threshold (20-60%). After every set termination, the participants reported pRIR. Results: Based on 2,972 unique measurements, we observed trivial to very large individual correlations between the objectively measured mean velocity and the pRIR (average r Discussion and conclusion: Our findings indicate that mean bar velocity and pRIR offer complementary-but not interchangeable-perspectives on strength training performance. Because pRIR was systematically influenced by exercise type, external load, proximity to failure, and set number, practitioners and researchers should interpret pRIR with caution and in the context of these variables.