Background: Physically manipulating objects according to texts can improve reading performance. This study examined whether these benefits can also be achieved via observing these manipulations or whether, because of an additional involvement of an action system, the physical manipulation might induce larger effects. Methods: In total, 134 second graders and 140 fourth graders completed tasks measuring reading comprehension, nonverbal intelligence, rapid automatised naming, working memory, morphological awareness and phonological awareness. Each child was assigned to one of three groups: rereading, observed manipulation and participant-performed manipulation. Those in the observed manipulation group were asked to reread the story while simultaneously watching a video of corresponding manipulations. Those in the participant-performed manipulation group were instructed to manipulate objects to represent the story's content. The next period was concerned with the practice effects of the manipulations. The children in the observed manipulation group were instructed to read a new story using the participant-performed manipulation approach. Those in the other two groups were asked to read the new story using the same strategies they had used in the former period. Results: The results for the acute improvement showed that, for the fourth graders, the participant-performed manipulation led to a greater improvement than the observed one, and both of the manipulations provided greater improvements than the rereading. Our examination of the practice effect indicated that the participant-performed manipulation group only had an advantage over the rereading group, not the observed manipulation group, in text comprehension as a result of experience with object manipulation. Conclusions: The current results suggest that the observed and physical manipulations make unique contributions to reading comprehension. In addition, these two manipulations lead to similar facilitating effects of subsequent object manipulation on text comprehension.