Imagine the gym of the future. It has rows of exercise devices, same as now, but the machines have sensors that can detect who is using them (maybe via RFID from your gym card) and how much poundage is being moved at any moment. For the cardio machines, your speed and distance would be measured, just as it is now.

Now imagine that each machine is networked to a server. Everyone in the gym works as a team, with their actions becoming the inputs for a wall-sized video game. Each gym would have a captain, and you'd play via the Internet against other gyms. The poundage you move on your machine might be, for example, adding speed or ammunition to the captain's guns, or making your team's avatar faster or more protected in some way. You can imagine a million game types in which the gym equipment's movements can feed into the action. The simplest game would be a Viking rowing boat, or dog sled, racing against another gym, or multiple gyms. The most complicated would be some sort of combat game where your vehicle's speed, shields, and weapons power are determined by the output of the exercisers.

You'd need strict supervision to make sure no one was so amped up by the game that he hurt himself on the machines. And the captain would need to coordinate when someone moved from one machine to another. For example, if you were being attacked and needed stronger shields, you might move your most buff teammate to the machine controlling shield power until the threat was over. If speed was most important, you'd put your speedsters on the treadmill. Or maybe at some point everyone would have to "lift" at the same time to get over an obstacle. The variations are limitless.

I wouldn't include free weights in this business model, just because it would get dangerous if people started rushing.

In the beginning of this business model, people would show up whenever they wanted and join games in progress. Later on, I can imagine captains recruiting stronger and faster players and forming leagues.

People will exercise harder if they are part of a team effort. And video games are so engaging that the time would fly.  If you have bad knees, or you can't run for any other reason, you can still be completely competitive in this team sport.  For guys who grew up playing team sports, that could be a big appeal.

Obviously this sort of gym wouldn't be for everyone. Perhaps during certain times of day, such as morning, the video game would be turned off, but the sensors would keep a running total of the poundage you are moving that day and compare it to your personal history. The theory is that you would keep working out until you reached or exceeded your daily average poundage no matter what mix of equipment you used to get there.  That would encourage you to diversify your workout without the need to keep track of your progress on every individual machine. Maybe it's just me, but I don't like to combine math with exercise.

My point is that gym equipment is dumb. But it won't stay that way.