Normally I think of Veronica Gallego. She had an incredible clip almost ten years ago straining bicep curls (I think David Guetta was playing in the gym). Then I learned that cry/straining was just the norm for her.
Well, Quiver me timbers!! Here's a Shake n' bake Schmorgesborg
https://www.girlswithmuscle.com/1407454/ https://www.girlswithmuscle.com/1482327/ https://www.girlswithmuscle.com/1307675/
How could I forget one of my absolute favorites, Jodi Boam.... Cute, beautiful and gives those hard quivery flexes quite often!
Hard straining quiver ez curl @:15
Posing practice, especially after training with muscles fatigued cause more quivers everywhere.
When those bis peak and she quivers I melt!
Kim Mi-Seon https://www.girlswithmuscle.com/534367/