The Claim

In young untrained men, performing 3 sets of resistance training per exercise results in greater lower-body strength and thigh muscle cross-sectional area gains compared to 1 set, with a 41% increase in lower-body strength and an 11% increase in thigh muscle size, but no significant difference is observed in upper-body muscle adaptations between the two set volumes.

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

What the research says

Supports is higher

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

Supports
46score
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

If young guys who don’t work out start doing 3 sets of leg exercises instead of 1, they’ll get stronger legs and bigger thigh muscles—41% stronger and 11% more muscle—but their arms and chest won’t see the same extra benefit from doing more sets.

See the scientific wording

In young untrained men, performing 3 sets of resistance training per exercise leads to greater strength and muscle mass gains in leg muscles compared to 1 set, with a 41% increase in lower-body strength and an 11% increase in thigh muscle cross-sectional area, while no such difference is observed in upper-body muscles.

Why this might work

When you do more sets of leg exercises, your leg muscles experience more total pulling force, which tells the muscle cells to build more protein and recruit more nerve signals to move the weight, making the legs stronger and bigger. Your arms don't respond the same way because they don't feel the same level of force during the same exercises.

Supported mechanismbased on 1 study

What the research says

1 study

  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

    If you're a young guy who's never worked out before, doing three sets of leg exercises instead of one makes your legs stronger and bigger, but doing extra sets doesn't help your arms or chest any more than one set does.

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.

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