There are also swimming "treadmills". I experienced a water jet a long time ago and it was ok, but I think these are a bit more sophisticated. These could be co

There are also swimming "treadmills". I experienced a water jet a long time ago and it was ok, but I think these are a bit more sophisticated. These could be cool, never been in one though. https://www.endlesspools.com/ https://www.endlesspools.com/ Edit: Looked into them, they're pretty cool. You can option them with a mirror on the bottom to do form work, they take up far less space than a real pool and the fastest can sustain a pace of 51s/100yard which is very very quick.