# Accentuated eccentric loading in lower-body resistance training: a systematic review of acute and chronic adaptations on strength, power, and speed outcomes

## TL;DR

This review examines how accentuated eccentric loading in lower-body training affects strength, power, and speed, finding it can improve performance but with uncertain benefits for sprinting and agility.

## Contribution

The study systematically reviews and compares acute and chronic effects of accentuated eccentric loading versus traditional resistance training on strength and power outcomes.

## Key findings

- Acute AEL improved explosive performance with 110%–120% concentric 1RM in squats or 10%–30% added body mass in jump drills.
- Chronic AEL training increased maximal strength by 9%–22% and jump height by 4%–11%, comparable to traditional training.
- Transfer of AEL benefits to sprint and change-of-direction speed was inconsistent and uncertain.

## Abstract

Accentuated eccentric loading (AEL) prescribes an eccentric load exceeding the paired concentric load, exploiting the muscle’s greater force capacity during lengthening. Evidence suggests benefits, but findings on its acute and chronic efficacy versus traditional resistance training (TRT) remain inconsistent. Uncertainties persist regarding acute potentiation, optimal eccentric-to-concentric ratios, and transfer to sport performance. This review synthesises current evidence, distinguishing acute from chronic outcomes and summarising prescription variables to guide practice.

This review followed PRISMA 2020 guidelines. PubMed, Scopus, Web of Science, and Embase were searched to June 2025 for acute and chronic trials where eccentric loading exceeded concentric loading in lower limb exercises. We included peer-reviewed acute and longitudinal trials in healthy humans that (i) applied Accentuated eccentric loading to lower-body resistance or jump exercises, (ii) compared AEL with a traditional isoinertial or equal-load condition, and (iii) reported at least one outcome related to maximal strength, jump performance, sprint speed or change-of-direction ability. Data on study design, AEL configuration (eccentric and concentric loads, movement type, loading method, volume and frequency) and performance outcomes were extracted. Standardized effect sizes were taken from the original articles where reported and summarized qualitatively; no new meta-analytic pooling was performed due to heterogeneity in study designs and incomplete reporting.

Twenty trials met the inclusion criteria. Acute studies showed that AEL enhanced explosive performance when eccentric intensity was set at 110%–120% of concentric one-repetition maximum (1RM) in back squats or when an additional 10%–30% of body mass was applied in dumbbell release jump drills. However, responses were variable, with very high loads or poor timing occasionally impairing performance. Chronic training programs reported maximal strength gains ranging from approximately 9%–22%, with jump height improvements between 4% and 11%. While these adaptations were generally superior or comparable to traditional training, the magnitude of transfer to sprint and COD performance was inconsistent. Certainty of evidence (GRADE) was moderate for strength outcomes due to consistent positive effects, but low to very low for speed outcomes due to imprecision and heterogeneity.

AEL is an effective method to enhance lower body maximal strength and explosive performance, particularly when applying 110%–120% 1RM in multi-joint lifts or adding 10%–30% body mass in jump drills. However, the transfer of these adaptations to sprint and change-of-direction speed remains uncertain. Due to the high heterogeneity of study protocols and small sample sizes, these findings should be interpreted with caution. Future research requires standardized reporting and larger randomized trials to optimize programming.