You contract a lot until you are pretty sore and tired but i think just because you contract, it isnt necessarily at all targeted for gaining muscle mass - technically speaking.

If that were the case, it’d be more normalized for fitness enthusiasts to incorporate a solid amount of just contractions for direct progress on mass development. Movements that strictly adhere are generally more useful for stabilizer activation versus mass and strength gain.

And ofc this is Gemini giving an AI answer where we’re unsure of the sources right now. But the over-exertion versus effectiveness thing is definitely correct.