Wow. That article is really fascinating. I wonder why the group that, when it comes down to it, got the positive reinforcement, did better than the group with the negative? Let's face it, cleaning hotel rooms can't be especially fun. But if a bunch of eggheads show up one day and tell you it's great exercise and keeping you healthy, suddenly you have an added personal benefit from your work that wasn't there before. Also, I bet that news got them thinking a bit while they worked, even if it was just thinking, "At least my job is keeping me healthy!"
So was it positive reinforcement from authority figures combined with positive self-talk? It's really intriguing.
I notice with weights and stretches I see a lot more success when I imagine the muscle or muscles doing their thing, imagine myself stretching another inch further or doing 3 more reps; I just get this weird feeling that it's working.