The infamous Shake Weight—a fitness contraption that is supposed to make your arm muscles stronger and make you look ridiculously stupid at the same time—is useless, says Wired UK:

Jerking this 5-pounder only got our max heart rate up to 114, which pales in comparison to a standard weightlifting session, let alone back-to-back sets of push-ups. More importantly, after a few days of use, our muscles didn't feel nearly as sore as they do from weightlifting. And, as everyone knows: no pain, no gain.

I suspected that much but, to be honest, it is sad to know that I've devoted countless hours to an exercise that doesn't burn any significant calories. If I had a Shake Weight, I would totally return it. [Wired UK]