this is not a silly question at all.
but the answer is: you cant really protect your eye from vitreal or retinal detachment. jogging/treadmill is not nearly enough force to have contributed to your PVD. you just got unlucky.
i guess if i were you i wouldnt take up kickboxing as a hobby, but other than that there is really nothing you could do to prevent vitreal or retinal detachments.
dont change your lifestyle for fear of PVD/RD. you're not doing anything wrong. there is nothing you could do...no activity, etc to affect a PVD/RD except JARRING head movements like the kind you get in FIGHTS and auto accidents. no normal/everyday action would have any affect one way or the other.