Sharing equipment is more than just good etiquette.
It’s cold out, it’s the first of the year, and the gym is busy, especially during after-work hours. “Working in” others on machines is standard procedure for peak times, not just as policy, but as basic courtesy. In addition to helping everyone move through their workout, you will actually burn more calories and improve your strength training this way.
The old school way of weight training was to do a set, rest, do another set, rest, and so on. This is called horizontal loading, and does nothing except add more sitting to your workout.
Vertical loading, on the other hand, entails moving to another exercise immediately after a set. Essentially, you are still resting the muscles that you just worked, while simultaneously working another group of muscles. Having a well-organized workout utilizing vertical loading keeps you moving through your workout more efficiently, while burning more calories as well.
For those unfamiliar with the concept of “working in” – it simply means sharing equipment throughout your sets. Once you finish a set and move on to another exercise, allow other people to use that piece of equipment before you return to it. If you come back for another set and someone is there, simply ask, “May I work in with you on this machine?” Your courtesy will be appreciated and your workout will benefit as well.