All the studies looked only at leg muscles in young people — we don’t know if the same results apply to arms, women, or older adults.

Scientific Claim

The available evidence on muscle fiber hypertrophy from low-load and high-load resistance training is limited to the quadriceps muscle in young adults, with no data from upper-body muscles or older populations, restricting generalizability.

Original Statement

“It needs to be mentioned that the results presented in this meta-analysis are specific to the lower-body musculature. Specifically, all studies collected muscle biopsy samples from the quadriceps femoris muscle group... Therefore, while indicative, the results presented herein cannot necessarily be generalized to the upper-body musculature.”

From study:The Effects of Low-Load Vs. High-Load Resistance Training on Muscle Fiber Hypertrophy: A Meta-Analysis

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 describes a methodological constraint of the included studies, not a causal or correlational effect. The authors explicitly state this limitation, and the language appropriately reflects scope, not inference.

Evidence from Studies

Supporting (1)

The Effects of Low-Load Vs. High-Load Resistance Training on Muscle Fiber Hypertrophy: A Meta-Analysis

Systematic Review With Meta-Analysis

Human

2020 Aug

This study found that we don’t yet know for sure if light or heavy weights work better for muscle growth, and it didn’t even look at older people or muscles in the arms—so we can’t say these results apply to everyone.

Contradicting (0)

No contradicting evidence found

Source Study

The Effects of Low-Load Vs. High-Load Resistance Training on Muscle Fiber Hypertrophy: A Meta-Analysis

Score: 39

DOI: 10.2478/hukin-2020-0013

Similar Assertions

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