Even though both muscle thickness and total lean mass went up after training, they didn’t change together in a predictable way—meaning one might not be a perfect stand-in for the other.

Scientific Claim

The lack of correlation between changes in muscle thickness and thigh lean tissue mass in both cluster and traditional set conditions suggests that these two measures may reflect different aspects of tissue adaptation, such as fluid shifts or non-muscle lean tissue changes, in resistance-trained individuals.

Original Statement

“No statistically significant correlations were found between changes in muscle thickness and lean mass for both the CS (R = 0.009) and TS (R = 0.506) groups.”

From study:Cluster sets and traditional sets elicit similar muscular hypertrophy: a volume and effort-matched study in resistance-trained individuals

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The claim correctly describes a correlational finding without implying causation. The language 'suggests' appropriately reflects the exploratory nature of the correlation analysis.

Evidence from Studies

Supporting (1)

Cluster sets and traditional sets elicit similar muscular hypertrophy: a volume and effort-matched study in resistance-trained individuals

Randomized Controlled Trial

Human

2025 Jun

The study found that two different ways of lifting weights made muscles thicker and legs leaner in similar ways, but the amount of thickening didn’t match up perfectly with the amount of lean mass gain—suggesting they’re measuring different things, like water or other tissues, not just muscle.

Contradicting (0)

No contradicting evidence found

Source Study

Cluster sets and traditional sets elicit similar muscular hypertrophy: a volume and effort-matched study in resistance-trained individuals

Score: 45

DOI: 10.1007/s00421-025-05712-6

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