Relationship between the number of repetitions in reserve and lifting velocity during the prone bench pull exercise : An alternative approach to control proximity-to-failure

Pérez-Castilla, A, Miras-Moreno, S, Weakley, J, and García-Ramos, A. Relationship between the number of repetitions in reserve and lifting velocity during the prone bench pull exercise: an alternative approach to control proximity-to-failure. J Strength Cond Res 37(8): 1551–1558, 2023—This study aimed to explore the goodness-of-fit and accuracy of both general and individual relationships between the number of repetitions in reserve (RIR) and the repetition velocity during the Smith machine prone bench pull exercise. Fifteen male sports science students completed 3 sessions separated by 48–72 hours. The first session was used to determine the bench pull 1 repetition maximum (1RM). The second and third sessions were identical and consisted of 3 single sets (60, 70, and 80% 1RM) of repetitions to momentary muscular failure separated by 10 minutes during the Smith machine prone bench pull exercise. General (i.e., pooling together the data from the 15 subjects) and individual RIR-velocity relationships were constructed from the data collected in the second session by pooling the data from the 3 loads (multiple-loads) or specifically for each load (load-specific). The 4 RIR-velocity relationship models were ranked by their goodness-of-fit as follows: individualload-specific (r = 0.93) > individualmultiple-loads (r = 0.83) > generalmultiple-loads (r = 0.65) > generalload-specific (r = 0.61). The accuracy when predicting the RIR in the third session based on the RIR-velocity equations obtained in the second session was acceptable and comparable for the 4 RIR-velocity relationship models (absolute errors ≤2 RIR). However, the 4 RIR-velocity relationship models significantly underestimated the RIR for ≥1 RIR and overestimated the RIR for 0 RIR. These results suggest that the 4 RIR-velocity relationship models are equally effective to quantify proximity-to-failure during the Smith machine prone bench pull exercise.