I recently purchased one of those arm blasters and can't help but think it's poorly designed.
Ordinarily, when I do barbell curls I strictly keep my upper arms at my side with the back of my arms even with my back. However, the bend in the arm blaster isn't very deep so I can't bring my arms taht far back. With the blaster on, the back of my upper arm is much closer to my chest than my back. This doesn't seem like proper form. If you watch this video you'll see what I mean, it demonstrates an ab blaster like the one I got - https://www.youtube.com/watch?v=Hzyj3er6jJQ
For a product that is supposed to help you have better form and keep you from cheating, I feel like this is forcing me to use bad form. Wouldn't it be better if it had a very deep curve that allowed you to keep your upper arms at your side but just prevented you from swinging your arms backwards, as if you had your back against a wall? That's how I always thought an arm blaster worked, are there models that work that way?
Are curls more effective if you keep your arms forward like this? If not, is there any benefit to using this thing if I do not cheat without using the blaster? This thing kind of forces my arms to be at an angle somewhere between regular barbell curls and breacher curls. It just feels weird.