At the gold's gym I joined a few months ago, I came upon two unusual cardio machines in the crossfit area.
The first was the Jacob's Ladder which reminded me of the time i used a versaclimber back before they became extinct. Using my whole body was way more intense than when I used a treadmill or bike. The second time i tried it, I grabbed onto the handrails, just using my legs. This reminded me of stepmill but easier to go faster on. The angle of the device keeps me from slouching like I sometimes do on the stepmill when going fast. Both times I pushed myself as hard as possible then rested, continuing when ready, keeping up for 15 mins.
The second piece of equipment they have is called a matrix s-drive, which you could also call a sledmill. It's a substitute for sled pushing, and while it doesn't feel exactly like using a prowler, I still got an intense workout from it. for 15 mins I did 50 step "bursts" resting just enough to begin again. Started out with resistance in the middle, began with a sprint but by the end turned into a fast walk.
Overall pretty cool for gyms that dont have alot of space for sleds. There's even a resistance harness you could sprint against but my running mechanics are shit.
Anyone else have experience with these?