A great way to test the effect it can have on your muscles is if you use thicker weights. You can partially experience this feeling by using a long, hard material towel, Wrap it several times around the dumbbell bar, then start the session with a biceps curl exercise. But I wish I could tell you that the towels can't always be a substitute for the Fat Gripz, because they are still made of soft material compared to the Gripz. The shape of the overall design is incompatible with its purpose, and can continue to move from it's position, as it does not lock onto the bar during exercise, Also not in line with human grip, as specific made as Fat Gripz.