Strong Support
causal
Analysis v2
History

In well-trained male judo athletes, six weeks of resistance training using either heavy weights to failure or light weights without failure increases the size and maximum strength of the elbow flexor...

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Pro
0
Against

Mechanism

Synthesis from 1 study

How it works

When judo athletes train with heavy or light weights, their arm muscles grow thicker because the lifting stretches and stresses the fibers, triggering growth signals — but since they don’t train to move fast, their nerves don’t learn to fire more quickly, so they don’t get better at generating...

Most probable mechanism

In Simple Terms

When judo athletes lift weights — whether heavy or light — their arm muscles are stretched and squeezed hard during each rep. This pulls on muscle fibers and builds up waste products like lactic acid, which signals the muscle to grow thicker over time. But because the training doesn’t involve fast, explosive movements, the nerves controlling those muscles don’t learn to fire more quickly or in better coordination, so the athletes don’t get faster at generating power. This is shown in 10.1371/journal.pone.0307841, where both training methods increased muscle size and static strength but not power.

Causal chain
1

Mechanical tension from resistance training activates mTORC1 signaling pathways in skeletal muscle fibers, initiating protein synthesis and myofibrillar hypertrophy — supported by the observed increases in elbow flexor muscle thickness in both heavy-load and light-load protocols.

Verified by multiple studies
which leads to
2

Metabolic stress from high-repetition sets (even without failure in light-load training) elevates intramuscular metabolites such as lactate and inorganic phosphate, further stimulating muscle growth through cellular swelling and anabolic signaling — consistent with hypertrophy outcomes in both training conditions.

Supported by evidence
which leads to
3

Maximal isometric force increases as a result of greater cross-sectional area from hypertrophy and potential improvements in muscle-tendon stiffness, without changes in motor unit firing rate or rate coding — explaining strength gains without power improvements.

Verified by multiple studies
which leads to
4

Power-generation capacity remains unchanged because neither training protocol includes high-velocity movements or explosive contractions sufficient to enhance neural drive, rate of force development, or fast-twitch fiber recruitment dynamics.

Verified by multiple studies

Evidence from Studies

Supporting (1)

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Contradicting (0)

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No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

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