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
1 study reviewed
In plain English

In people who have not previously trained, 8 weeks of traditional weightlifting exercises for the biceps leads to greater increases in muscle size and strength compared to a different type of resistance exercise that involves holding a static position under load.

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 initial muscle and strength gains in this population.

Why this might work

When you lift and lower weights through a full range of motion, your muscle fibers are stretched and pulled with more force and for longer periods, which triggers more muscle growth and stronger nerve signals to the muscles. Holding a weight still doesn’t stretch or move the muscle as much, so it doesn’t stimulate growth or strength gains as much.

Supported mechanismbased on 1 study

What the research says

1 study

  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 weightlifting exercises for the biceps made their muscles bigger and stronger more than holding heavy weights still. The study showed this clearly after 8 weeks of training.

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

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