The Claim

In untrained individuals, performing three sets per exercise results in significantly greater gains in lower-body strength and hypertrophy compared to performing one set per exercise, but does not result in significantly greater gains in upper-body strength and hypertrophy.

Source: How Often Should You Train a Muscle? - This NEW Study Is Epic

What the research says

Supports is higher

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

Supports
54score
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.

Quantitative
3 studies reviewed
In plain English

In people who have not trained before, doing three sets of an exercise builds more strength and muscle in the legs than doing one set, but does not build more strength or muscle in the arms compared to one set.

See the scientific wording

In untrained individuals, three sets per exercise produce significantly greater lower-body strength and hypertrophy gains than one set, but not upper-body gains.

Why this might work

When you lift heavier weights with more repetitions in leg exercises, the muscles experience more tension and burn more energy, which turns on a molecular switch that tells the muscle to build more protein and grow larger. Larger muscles can produce more force, making you stronger. This effect happens strongly in the legs but not in the arms, because the legs have more muscle mass and respond more to increased workload.

Verified mechanismbased on 3 studies

What the research says

3 studies

  1. Study: DISSIMILAR EFFECTS OF ONE‐ AND THREE‐SET STRENGTH TRAINING ON STRENGTH AND MUSCLE MASS GAINS IN UPPER AND LOWER BODY IN UNTRAINED SUBJECTS

    In people who haven't trained before, doing three sets of leg exercises builds more strength and muscle than doing just one set, but for arm and shoulder exercises, one set works just as well as three sets.

  2. Study: Early phase adaptations of single vs. multiple sets of strength training on upper and lower body strength gains

    For people who’ve never lifted weights before, doing three sets of leg exercises builds stronger legs than doing just one set, but for arm exercises, one set works just as well as three sets.

  3. Study: DISSIMILAR EFFECTS OF ONE‐ AND THREE‐SET STRENGTH TRAINING ON STRENGTH AND MUSCLE MASS GAINS IN UPPER AND LOWER BODY IN UNTRAINED SUBJECTS

    In people who’ve never lifted weights before, doing three sets of leg exercises builds bigger, stronger legs than doing just one set—but for arm exercises, one set is just as good as three sets.

Related videos

How Often Should You Train a Muscle? - This NEW Study Is Epic

House of Hypertrophy

How Often Should You Train a Muscle? - This NEW Study Is Epic

Read analysis

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 3 supporting studies

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

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.