Massage is brilliant as a management technique to keep horses in good shape. It's pretty limited in its application, but what it does do (keep muscles soft and knot free) is excellent when done by the right person, and can have many knock on effects. Tension in a horse (or even human) can have a pretty significant impact on their way of moving.
My horse gets a facia release every month, sometimes more. Couldn’t ride without it, it helps your horse soooo much😍