There is no specific time and it 100% dependent on the subject. High level athletes in good condition will take much longer to see joint and tendon function differences compared to a non athlete. I believe you begin to see this whenever it is that the muscle begins to fatigue
I don't have literature that support my vieuw but walking on the floor ask for power to propell your body and that isn't necessary on treadmill. Therefore there must be an differenty between walking over an floor and on an treadmill. Personally i feel that the buttock muscle isn't so active on the treadmill as on the floor by hiel strike action.
But again i have found no prove for this hypothesis.