Hernández-Belmonte, Alejandro; Courel-Ibáñez, Javier; Conesa-Ros, Elena; Martínez-Cava, Alejandro; Pallarés, Jesús G.

Journal of Strength and Conditioning Research: November 2022 - Volume 36 - Issue 11 - p 2992-2999, doi: 10.1519/JSC.0000000000004060

PURPOSE:

To analyze the potential of the level of effort as an immediate indicator of the relative resistance load (percentage of one-repetition maximum [%1-RM]) and the between rep rest volume of an individual while performing the bench press, full squat, shoulder press, and prone bench pull using three specific objectives:

1. To examine the between subject (inter-subject) and within individual subject variability in the number of repetitions (reps) to failure (nRM) against the %1-RM lifted (adjusted by the individual velocity).

2. To investigate the relationship between the number of reps completed and velocity loss reached.

3. To study the influence of the subject's strength level on the aforementioned parameters.

PROCEDURES:

30 subjects with low (n = 10), medium (n = 10), and high (n = 10) relative strength levels completed two rounds of nRM tests using 65, 75, 85, and 95% 1-RM in the four exercises.

The velocity of all reps was monitored using a linear transducer. Between subject and within inter-subject and intra-subject variability analyses included the 95% confidence intervals (CIs) and the standard error of measurement (SEM), respectively. Coefficient of determination (R2) was used as the indicator of relationship.

CONCLUSIONS:

nRM showed a limited inter-subject (CI ≤ 4 repetitions) and a very low intra-subject (SEM ≤1.9 repetitions) variability for all the strength levels, %1RM, and exercises analyzed.

A very close relationship (R2 ≥ 0.97) between the number of repetitions completed and the percentage of velocity loss reached (from 10 to 60%) was found.

These findings strengthen the level of effort as a reliable, precise, and practical strategy for programming resistance training.

IN PLAIN ENGLISH:

When performing any strength training exercise, use proper form, exude high effort, and in the majority of times attempt to reach the point of momentary muscle fatigue.