Accepted for/Published in: JMIR Research Protocols
Date Submitted: Oct 14, 2024
Date Accepted: Jul 21, 2025
Effects of Performing Eccentric Contractions to Failure After Concentric Muscle Failure In Resistance Training Sessions: Protocol for a Within-Participant Randomized Trial
ABSTRACT
Background:
The hypertrophic response to resistance exercise protocols has been shown to be associated with volume-load, a surrogate of the gross mechanical work produced during training sessions. Performing repetitions until concentric muscle failure (MFCON ) – or close to it – has also been shown to be effective in promoting muscle hypertrophy. However, when MFCON occurs, one can still perform eccentric muscle actions, which could contribute to increase the volume-load of the session.
Objective:
The objective of this study will be to verify whether performing eccentric contractions to failure (MFEXC) after the occurrence of concentric muscle failure (MFCON ) enhances the neuromuscular adaptations already observed after a traditional resistance training protocol to MFCON.
Methods:
In a randomized, controlled, within-participant design, untrained young adult females will perform two resistance training protocols, each with one of their upper limbs: traditional training to MFCON (TRAD) and training with sets to MFCON followed by exclusively eccentric contractions to MFEXC (ECC+). The protocols will be performed at an intensity range of 9-12 maximum repetitions (considering MFCON for load adjustment) over 10 weeks, with two weekly sessions consisting of six sets with two minutes of rest per set. The exercise performed will be unilateral elbow flexion. Markers of muscle function (maximal, explosive, and powerful strength) and body composition (muscle thicknesses of different portions of the biceps brachii and brachialis muscles, circumferences of different portions of the arm, and muscle and fat masses) will be measured before and after the interventions and compared between limbs and over time using two-way ANOVAs. The level of significance will be p < 0.05.
Results:
The project was approved by the Research Ethics Committee (CEP) with CAAE number 76595923.8.0000.5659. Seven participants completed the intervention, with data collection from March to July 2024.
Conclusions:
Further data collection is planned for the first half of 2025, and a manuscript is expected to be published in the second half of 2025. Clinical Trial: Does not apply.
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