Adaptive rowing is a special category of races for those with physical disabilities. Under FISA rules there are 5 boat classes for adaptive rowers; mixed (2 men and 2 women plus cox) LTA (Legs, Trunk, Arms), mixed intellectual disability (2 men and 2 women plus cox) LTA (Legs, Trunk, Arms), mixed (1 man and 1 woman) TA (Trunk and Arms), and men's and women's AS (Arms and Shoulders). Events are held at the World Rowing Championships and were also held at the 2008 Summer Paralympics.
The rowing machine itself is unlike any other on the market with its patented water filled flywheel. It is hard to exactly copy the action of a scull on the water, but the mechanics of the flywheel spinning in water comes in a close second on dry land. The fact that the water is 800 times denser than air means that there is no need for any extra resistance or dampening that you will find in normal air rowers. The faster you pull, the more resistance is generated giving it infinite variability. However, if you want to be able to practice rowing with a faster stroke, you will have to reduce the amount of water in the tank unlike an air rower where you just have to adjust the baffle.