The Claim

Eccentric-only resistance training performed twice weekly for five weeks at half the total volume of concentric-eccentric training produces similar increases in isometric and eccentric strength (11–16%) and muscle thickness (9.7%) in untrained young adults.

Source: Comparison between concentric-only, eccentric-only, and concentric–eccentric resistance training of the elbow flexors for their effects on muscle strength and hypertrophy

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
55score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Cause and effect
1 study reviewed
In plain English

In untrained young adults, performing eccentric-only resistance training twice a week for five weeks at half the total workload of regular training results in the same increases in muscle strength and thickness as full concentric-eccentric training.

See the scientific wording

Eccentric-only resistance training performed twice weekly for five weeks at half the total volume of concentric-eccentric training produces similar increases in isometric and eccentric strength (11–16%) and muscle thickness (9.7%) in untrained young adults, suggesting eccentric contractions alone can drive substantial neuromuscular adaptations without concentric effort.

Why this might work

When muscles lengthen under heavy load, the force pulls on the muscle fibers in a way that triggers a signal inside the cells to build more contractile proteins and add new structural units. This makes the muscle thicker and stronger, even without lifting the weight up.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: Comparison between concentric-only, eccentric-only, and concentric–eccentric resistance training of the elbow flexors for their effects on muscle strength and hypertrophy

    Doing just the lowering part of a bicep curl, half as much as doing both up and down, made people just as strong and their muscles just as big as doing the full exercise — proving you don’t need to lift the weight to get strong.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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