If the body can't be trained, then it seems a tennis ball would just periodically wake you up throughout the night. Unless I find some data, I guess I'll be using the SlumberBump (or something similar) indefinitely to physically prevent rolling to the back.
Thanks. I'm actually using a SlumberBump at the moment, which easily forces my body to stay on the side but doesn't actually cause the kind of pain I expect a tennis ball would provide from an attempt to roll to the back. I'm a little curious if the lack of pain makes it less likely that my body could be trained? Is there any evidence that a tennis ball can actually train the body to stay off the back?
It seems to be a common recommendation to attach one or more tennis balls to your back to treat mild sleep apnea, but I'm not finding a lot of detail on how well it actually works.
I'd be interested in hearing about the experience of anyone who's tried it. Does the pain of rolling onto your back wake you up? Is it true that your sleeping body somehow learns to stay off your back and you can eventually stop using the tennis balls?