The Claim

In young women aged 21.8 ± 3.4 years, performing resistance training three times per week for 10 weeks with either constant or varied exercises results in similar increases in muscle thickness (7.5–19.3% vs. 7.8–17.7%) and one-repetition maximum strength (24.4–32.1% vs. 29.0–30.1%) for the leg press and leg extension, indicating that exercise variation does not confer a superior adaptive advantage for muscle growth or strength gains in this population.

Source: Muscle Hypertrophy and Strength Adaptations to Systematically Varying Resistance Exercises

What the research says

Supports is higher

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

Supports
48score
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 young women, doing resistance training three times a week for 10 weeks with either the same exercises or varied exercises leads to similar improvements in leg muscle thickness and strength, meaning changing exercises does not produce better results.

See the scientific wording

In young women aged 21.8 ± 3.4 years, performing resistance training three times per week for 10 weeks with either constant or varied exercises results in similar increases in muscle thickness (7.5–19.3% vs. 7.8–17.7%) and one-repetition maximum strength (24.4–32.1% vs. 29.0–30.1%) for the leg press and leg extension, indicating that exercise variation does not confer a superior adaptive advantage for muscle growth or strength gains in this population.

Why this might work

When you lift weights, your muscle fibers get stretched and squeezed, which tells them to grow stronger. Whether you do the same exercise every time or switch it up, as long as you're lifting with enough effort and pushing your muscles hard, they respond the same way — so changing exercises doesn't make them grow more or get stronger faster.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: Muscle Hypertrophy and Strength Adaptations to Systematically Varying Resistance Exercises

    For young women, doing the same leg exercises every workout is just as good for building muscle and strength as switching up the exercises each session — changing things up doesn’t give you any extra benefit.

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

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

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