I just call these a cable curl, which is literally all they are.

I just focus on allowing my bicep to fully stretch, while emphasizing my elbow staying behind me ( I don’t have the greatest flexibility so this is as far as I can go comfortably). Idealistically, you’d be able to brace yourself with your free hand, but that wasn’t in the cards for how this cable machine is set up.

Normally I would do these in the 6-8 rep range, but my elbows were feeling a bit questionable today so I decided to lower the weight and up the reps (remember to practice safe sets!)