i have had aqua therapy (for my rib). this particular therapist gave me a lot of theraband stuff and i was like, well, i can do that, but only if the theraband does not stretch (isometric).

i have also had aqua bed. you lay on this bed where water jets on the plastic sheet that is under you, giving you a water massage. that was great. the machine is quite expensive so the only place i ever saw it was at the med school. however, if you put on a bathing suit you can probably make one at home, only the water won't be heated.

i would use saw horses and two by fours, nail a tarpaulin to the two by fours. find some bored child to spray the bottom with a pressure nozzle.