Acute muscle swelling following resistance exercise demonstrates an inconsistent relationship with long-term muscle hypertrophy, and this relationship may be dependent on the specific muscle group examined; therefore, further research is required to establish whether acute muscle swelling possesses reliable predictive value for long-term hypertrophy outcomes.

When muscles are worked hard, they swell temporarily because of fluid buildup from metabolic byproducts like lactate. This swelling is not what makes muscles grow, but it happens at the same time as signals that tell the muscle to build more protein. Whether the muscle grows over time depends on how much total work is done and how much force the muscle fibers experience, not on how swollen it gets right after exercise. Different muscles may swell differently based on their size and blood flow, which is why swelling doesn't always predict growth the same way everywhere in the body.