Effects of Performing Eccentric Contractions to Failure After Concentric Muscle Failure in Resistance Training Sessions: Protocol for a Within-Participant Randomized Trial
Bibliographic record
Abstract
Background Resistance training is a well-established strategy to promote muscle hypertrophy and strength gains. Performing sets to concentric muscle failure (MFCON) is commonly used to maximize neuromuscular adaptations. However, after reaching MFCON, there is a remaining capacity for eccentric contractions that could be used. Increasing eccentric contraction volume may represent a promising and practical alternative to enhance training volume load and optimize adaptations, although its effectiveness in this specific application has not yet been tested. Objective This study aims to investigate whether performing additional eccentric contractions to eccentric muscle failure (MFEXC), after the occurrence of MFCON, enhances neuromuscular and morphological adaptations beyond those promoted by a traditional protocol to MFCON. Methods In a randomized within-subject design, untrained young adult females will perform 2 upper-limb resistance training protocols over 10 weeks, including traditional (TRAD) training to MFCON and a training protocol (ECC+) consisting of sets to MFCON followed by eccentric-only contractions to MFEXC. Each arm will be assigned to one of the protocols. Sessions (twice per week) will consist of 6 sets of unilateral elbow flexion with a load between 9 and 12 repetition maximum, with 2-minute rest intervals. Muscle function (isometric, concentric, and eccentric strength) and body composition (biceps brachii and brachialis muscle thickness and dual-energy x-ray absorptiometry [DXA]–based analysis) will be assessed pre and post intervention. Comparisons between limbs and across time will be analyzed using 2-way ANOVA. The level of significance will be set at P<.05. Results As of July 2024, a total of 7 participants have completed the intervention. Data collection was conducted between March and July 2024, with a new phase planned for the first half of 2025. Manuscript submission is expected in the second half of 2025. Conclusions If the hypothesis is confirmed, the ECC+ protocol may represent a practical, simple, and low-cost strategy to increase training volume and optimize strength and hypertrophy outcomes. This study may contribute to evidence-based resistance training prescriptions, particularly for women, and support the use of additional eccentric contractions as an effective tool to enhance localized muscle adaptations. International Registered Report Identifier (IRRID) DERR1-10.2196/67537
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.019 | 0.021 |
| Meta-epidemiology (narrow) | 0.009 | 0.003 |
| Meta-epidemiology (broad) | 0.015 | 0.005 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.004 | 0.003 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.004 | 0.003 |
| Research integrity | 0.009 | 0.010 |
| Insufficient payload (model declined to judge) | 0.054 | 0.010 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".