The Claim

In untrained individuals, 8 weeks of isotonic resistance exercise of the elbow flexors produces a significantly greater increase in muscle thickness and estimated one-repetition maximum compared to eccentric quasi-isometric resistance exercise.

Source: Isotonic Resistance Exercise Outperforms Eccentric Quasi-Isometric Resistance Exercise for Increasing Elbow Flexor Muscle Thickness and Estimated One-Repetition Maximum in Untrained Individuals: Exploring the Influence of Sex and Volume.

What the research says

Supports is higher

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

Supports
45score
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
2 studies reviewed
In plain English

In people who have not previously trained, performing 8 weeks of traditional weightlifting exercises for the biceps leads to greater increases in muscle size and strength compared to performing exercises that involve holding a weight in a stretched position without moving it.

See the scientific wording

In untrained individuals, 8 weeks of isotonic resistance exercise of the elbow flexors results in a significantly greater increase in muscle thickness (6.7% ± 3.9%) and estimated one-repetition maximum (19.6% ± 8.5%) compared to eccentric quasi-isometric resistance exercise (4.0% ± 3.3% and 12.8% ± 6.2%, respectively), suggesting isotonic training may be more effective for hypertrophy and strength gains in this population.

Why this might work

When you move a weight through a full range of motion, the muscle stretches and contracts forcefully, pulling on its fibers more than when holding a weight still. This pulling activates signals inside the muscle cells that tell them to build more protein, making the fibers thicker and stronger over time.

Supported mechanismbased on 2 studies

What the research says

2 studies
  1. Study: Isotonic Resistance Exercise Outperforms Eccentric Quasi-Isometric Resistance Exercise for Increasing Elbow Flexor Muscle Thickness and Estimated One-Repetition Maximum in Untrained Individuals: Exploring the Influence of Sex and Volume.

    In people who’ve never lifted weights before, traditional bicep curls with weights led to bigger muscles and stronger arms than holding a weight still in a stretched position. The study shows the moving exercise worked better.

  2. Study: Isotonic Resistance Exercise Outperforms Eccentric Quasi-Isometric Resistance Exercise for Increasing Elbow Flexor Muscle Thickness and Estimated One-Repetition Maximum in Untrained Individuals: Exploring the Influence of Sex and Volume.

    In people who’ve never lifted weights before, traditional bicep curls made their arms bigger and stronger than holding a weight still in a stretched position. The study proved the curls worked better.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 2 supporting studies

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