I got a trampoline for the garden some years ago when my knees were bad - it is a great surface for rolling around on, kneeling stretching etc are all a lot easier as there is not single point of contact so kneeling down, which was agony on a hard surface, was absolutely fine on the trampoline apron, and I used to go out twice a day and do about a thousand bounces, which I intend to do again once the weather warms up.
As soon as there is the slightest green on the fruit trees I start to do at least one session a day. I really ought to get one of those little 'rebounder' things for indoors.