In trained men, when one muscle repair protein (IGF-IEa) goes up after a workout, the other one (MGF) tends to go up too — they seem to work together.

Scientific Claim

There is a moderate to strong positive correlation (r = 0.74) between the increases in IGF-IEa and MGF mRNA expression in the vastus lateralis muscle of strength-trained men 48 hours after heavy resistance exercise, suggesting coordinated regulation of these isoforms.

Original Statement

“A positive correlation (r = 0.74, p < 0.05) was found between the changes of IGF-IEa and MGF mRNA expression at 48 hours after the exercise.”

From study:Recovery after Heavy Resistance Exercise and Skeletal Muscle Androgen Receptor and Insulin-Like Growth Factor-I Isoform Expression in Strength Trained Men

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 uses 'correlation' and reports the r-value and p-value, avoiding causal language. The design supports correlational analysis.

Evidence from Studies

Supporting (0)

No supporting evidence found

Contradicting (1)

Recovery after Heavy Resistance Exercise and Skeletal Muscle Androgen Receptor and Insulin-Like Growth Factor-I Isoform Expression in Strength Trained Men

Cohort Study

Human

2011 Mar

The study shows that two muscle repair signals go up after heavy lifting, but it doesn’t measure how closely they move together, so we can’t say they’re strongly linked like the claim says.

Source Study

Recovery after Heavy Resistance Exercise and Skeletal Muscle Androgen Receptor and Insulin-Like Growth Factor-I Isoform Expression in Strength Trained Men

Score: 30

DOI: 10.1519/jsc.0b013e318202e449

Similar Assertions

After doing heavy leg workouts, the muscles of trained men show a big spike in two specific proteins (IGF-IEa and MGF) that help repair muscle damage, and this spike happens about two days later.

82%

The more the thigh swells after a workout, the more the MGF repair protein increases — suggesting MGF might be triggered by physical stretching or swelling in the muscle.

78%