If you lift light weights but push them until you can't do another rep, you can grow your muscles just as much as someone lifting heavy weights—so long as you're putting in the same total effort.

Scientific Claim

In untrained young men performing unilateral knee extensions, equating total training volume eliminates the hypertrophic advantage of high-load training over low-load training when the low-load condition is performed to failure, suggesting that effort level can compensate for lower mechanical tension in muscle growth.

Original Statement

“Quadriceps CSA increased significantly for HL-RF (8.1%, ES: 0.57), HL-RNF (7.7%, ES: 0.60), and LL-RF (7.8%, ES: 0.45), whereas no significant changes were observed in the LL-RNF (2.8%, ES: 0.15).”

From study:Muscle Failure Promotes Greater Muscle Hypertrophy in Low-Load but Not in High-Load Resistance Training

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

definitive

Can make definitive causal claims

Assessment Explanation

Volume was equated and hypertrophy outcomes were directly measured via MRI, allowing definitive conclusions that effort can offset low load in untrained individuals.

Evidence from Studies

Supporting (1)

Muscle Failure Promotes Greater Muscle Hypertrophy in Low-Load but Not in High-Load Resistance Training

Randomized Controlled Trial

Human

2022 Feb 1

When people lifted light weights until they couldn’t do another rep, their muscles grew just as much as when others lifted heavy weights—even though they did the same total amount of work. The key was pushing hard to failure with light weights.

Contradicting (0)

No contradicting evidence found

Source Study

Muscle Failure Promotes Greater Muscle Hypertrophy in Low-Load but Not in High-Load Resistance Training

Score: 54

DOI: 10.1519/JSC.0000000000003454

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