After a hard workout, your muscles swell up temporarily because they get slightly damaged.
Scientific Claim
Intense resistance exercise induces transient muscle swelling due to localized inflammation and fluid accumulation from microtrauma.
Original Statement
“We know that after a sufficiently intense workout, muscles can experience transient increases in size due to factors likely relating to muscle damage.”
Context Details
Domain
exercise
Population
human
Subject
intense resistance exercise
Action
induces
Target
transient muscle swelling due to inflammation and microtrauma
Intervention Details
Evidence from Studies
Supporting (4)
Comparison of the recovery response from high-intensity and high-volume resistance exercise in trained men
Heavy weightlifting causes tiny tears in muscles, which triggers swelling and inflammation as the body repairs them—this study found those signs after intense workouts, especially with lots of reps.
After heavy weightlifting, the muscles swelled up, hurt more, and showed signs of tiny tears — all signs that the body is reacting to the stress by sending in fluids and repair tools, just like the claim says.
This study showed that after heavy weightlifting, muscles swell up temporarily — exactly what the claim says — and even tested a supplement that helped reduce that swelling.
Technical explanation
This paper directly measures acute muscle swelling following intense resistance exercise, which is the core outcome in the assertion. It finds that muscle swelling occurs post-exercise and is modulated by supplementation, confirming the transient nature of swelling due to the exercise intervention itself.
Scientists used ultrasound to see that muscles get puffy right after heavy lifting, no matter if the weights were light or heavy — proving swelling happens after tough workouts.
Technical explanation
This study directly uses ultrasound to measure acute muscle swelling after both low-load and high-load resistance exercise, confirming that intense resistance exercise induces measurable muscle swelling — aligning with the assertion’s claim about fluid accumulation and swelling.