From this evening’s Legal Mirror 《法制晚报》, three ways the Spring Festival can hurt your lower back:
In figure 1, the traditional 45° bow stresses the lower back 10 times more than lying down, slouching while playing mahjong (fig 2) 5 times, and carrying heavy objects (fig 3) 3 times. So stop mixing tiles and go out to a temple fair already!
Image taken from the Legal Mirror article.