Developing a Repetition-Based Inter-Set Rest Adjustment Method in Resistance Training

Abstract

Background:

This study aimed to develop an objective, repetition-based method for inter-set rest adjustment in resistance training (RT), addressing limitations of fixed and self-selected intervals.

Hypothesis:

The adjustable protocol would yield greater repetition volume, higher velocity, and lower fatigue than the fixed protocol, with reduced time cost compared with the self-selected protocol.

Study Design:

Crossover randomized trial.

Level of Evidence:

Level 2.

Methods:

A total of 20 young adults completed 3 RT protocols in randomized order: fixed, self-selected, and adjustable. Each protocol involved 5 sets of bench press and bench pull at approximately 75% 1 repetition maximal, performed close to failure. The protocols differed in inter-set rest strategy: fixed (3-minute rest), self-selected (participant-determined), and adjustable (based on previous set repetition count).

Results:

Our findings indicated that the self-selected and adjustable protocols resulted in significantly greater repetition volume compared with the fixed protocol (F = 7.0; P = 0.003). Although the self-selected and adjustable protocols exhibited significantly higher fastest set velocity than the fixed protocol (F = 3.5, P = 0.04), the practical difference was only 0.01 m/s. In addition, no significant main effects of protocol were observed in mean set velocity, blood lactate concentration, or perceived exertion (F = 1.1-2.4; P = 0.10-0.58). In terms of time efficiency, the fixed protocol was the most efficient, followed by the adjustable protocol, with the self-selected protocol being the least efficient.

Conclusion:

People using the adjustable protocol achieved greater repetition volume without increased metabolic stress or perceived exertion compared with the fixed 3-minute rest. Although the adjustable protocol sacrifices some time efficiency compared with the fixed protocol, it remains more efficient than the self-selected approach.

Clinical Relevance:

The repetition-based inter-set rest adjustment approach can serve as a feasible alternative to both fixed and self-selected inter-set rest approaches in RT.