In the comics she was never as bulky as the Hulk. Way more jacked supermodel than power lifter. Recently they have made her much more bulky but in that form she loses a lot of the control she normally has.
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I don't think thats correct. Her powers seem to work the same way as Banner. She's just way more mentally stable than Banner, thats why she was in she-hulk form 24/7. Lately in the comics she's having a lot more turmoil. I think that's why she goes back and forth from human form and bulky She-hulk form instead of being in the middle at all times.