A single workout using concentric knee extensions raises the activity of specific muscle genes (PGC-1α-1, PGC-1α-4, IGF-1Ea, IGF-1Eb), while a single workout using eccentric knee extensions raises different but partially overlapping genes (PGC-1α-4 and IGF-1Ec), showing that the type of muscle contraction influences which genes are activated.

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Pro

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Against

Evidence from Studies

Supporting (1)

33

Community contributions welcome

33

Effect of different muscle contraction mode on the expression of Myostatin, IGF-1, and PGC-1 alpha family members in human Vastus Lateralis muscle

Randomized Controlled Trial

Human

2020 Dec

This study found that two types of leg exercises — pushing up and lowering down — each turn on different sets of genes in the muscle, but both turn on one same gene. This matches exactly what the claim says.

Contradicting (0)

0

Community contributions welcome

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.

Source Study

Effect of different muscle contraction mode on the expression of Myostatin, IGF-1, and PGC-1 alpha family members in human Vastus Lateralis muscle

Score: 33

DOI: 10.1007/s11033-020-06017-x

Similar Assertions

Both concentric and eccentric knee extensions increase PGC-1α-4 mRNA expression in healthy young men, but neither type of exercise produces a significantly larger increase than the other.

33

0

86%

After one session of knee extension exercises—whether lowering or lifting the weight—there is no measurable change in the levels of myostatin mRNA in the thigh muscle of healthy young men, when tested right after the workout.

33

0

75%