Pérez-Castilla, Alejandro; Miras-Moreno, Sergio; Janicijevic, Danica; García-Ramos, Amado

Journal of Strength and Conditioning Research 37(5):p 1001-1008, May 2023. | DOI: 10.1519/JSC.0000000000004365

PURPOSE:

To discuss both general and individual relationships between the magnitude of velocity loss (%VL) and the percentage of performed repetitions with respect to the maximal number of repetitions that can be completed to muscle failure (%Rep) with the Smith machine prone bench pull exercise (i.e., bent-over row/BOR).

PROCEDURES:

Fifteen male subjects completed a pre-test to determine the bench pull/BOR one-repetition maximum (1-RM) and two other experimental sessions separated by 48–72 hours. In each experimental session, subjects randomly performed single sets of repetitions to failure separated by 10 minutes using 60%, 70%, and 80% of the 1-RM with bench pull/BOR exercise.

CONCLUSIONS:

Individual %Rep-%VL relationships were better than general %Rep-%VL relationships with all three percentages of the 1-RM.

However, the accuracy (absolute errors) in estimating the %Rep during the second testing session based on the %Rep-%VL equations obtained in the first testing session did not differ between the individual and general %Rep-%VL equations in 8 of 9 comparisons.

The absolute errors between the actual and predicted %REP were unacceptable in 11 of 18 comparisons, and acceptable in 7 of 18 comparisons, which suggests the %Rep cannot be estimated with high degree of accuracy from VL recordings during bench pull/BOR regardless of whether individual or general Rep-%VL relationships are considered.

IN PLAIN ENGLISH:

Decades of legitimate and relevant research has been accomplished which has gleaned many valuable results with which to apply to training programs. However, lately there has been a lack of new metrics to measure/study (READ: to an extent, we are running out of legitimate topics to study as the most relevant have been studied to death). Aside from that and relevant to this study: There are too many factors to consider when comparing resistance velocity and respective reps to muscle fatigue with various percentages of a 1-RM, such as muscle fiber type (i.e., slow vs. fast MHC), their distribution in the acting muscles, diet/energetics, and the magnitude of effort applied.