Exercise type, training load, velocity loss threshold, and sets affect the relationship between lifting velocity and...

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.

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.

Based on 2,972 unique measurements, we observed trivial to very large individual correlations between the objectively measured mean velocity and the pRIR (average r² = 0.3 for both squat and bench press). Type of exercise (squat or bench press), velocity loss threshold, load, and sets affected the pRIR for a given mean velocity. Sex (females vs. males) and training weeks were unrelated to pRIR.

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.