Sorry, but everything you wrote is completely false. It wouldn't take "months" to heal from anything she might theoretically break. Besides, she did the Apple commercial very recently, and her 1989 tour is over. TS has no upcoming albums to promote and no scheduled concerts. Dancers learn how to land or fall without injuring themselves. She was probably also wearing pads underneath her clothes. Even the treadmill was likely padded, and the tread itself is just rubber. It's even possible the treadmill is CGI. With careful choreography, and a team of people helping her figure out just the right angle to shoot from, there is absolutely no reason why she couldn't have done the pratfall herself.