A physicist at the gym

When I go to my gym, I sometimes see people lifting weights in physically inappropriate ways. By “physically inappropriate” I don’t mean that they exhibit poor, injury-inducing form or that they use weights that are dangerously heavy or ineffectually light. I mean that they don’t, to use the language of physics, do much work. First defined in the 1830s by Gaspard-Gustave Coriolis, work entails moving a force’s point of application. If you’re handling a barbell, dumbbells, or other free weights, doing work means raising the weight’s center of mass against the pull of Earth’s gravitational field. But if you don’t raise the weight, if you move it about in a horizontal plane, your workout will be workless and quite possibly worthless. One near-workless routine I’ve witnessed involves hoisting a weight above your head while simultaneously bending at the knees, thereby ensuring that weight remains at the same height. There’s no doubt that the woman in this video is doing work as she raises her own center of mass and those of two 45-pound plates and a 45-pound bar.