The Claim

High-load and low-load resistance training produce comparable muscle hypertrophy, with cross-sectional area increases of 7-12%, in healthy adults aged 18-45 when performed to muscle failure with adequate volume, and there is no significant difference between the two methods (standardized mean difference = 0.35, 95% confidence interval [0.20–0.50], p = 0.012).

Source: Comparing High-Load and Low-Load Endurance Training for Strength and Hypertrophy: A Systematic Review and Meta-Analysis

What the research says

Challenges is higher

Challenge is ahead, but a single strong supporting study can change this.

Supports
0score
Challenges
39score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

Lifting heavy weights and lifting lighter weights both build muscle about the same amount in healthy adults, as long as you do enough reps until you can't lift anymore.

See the scientific wording

High-load and low-load resistance training produce comparable muscle hypertrophy (cross-sectional area increase 7-12%) in healthy adults aged 18-45 when performed to muscle failure with adequate volume, with no significant difference between methods (SMD = 0.35, 95% CI [0.20–0.50], p = 0.012).

What the research says

1 study
  1. Study: Comparing High-Load and Low-Load Endurance Training for Strength and Hypertrophy: A Systematic Review and Meta-Analysis

    The study looks at the same types of weight training as the claim, but it says results are mixed and doesn't back up the specific numbers given, so it doesn't fully support the claim.

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.