Under TEX. PEN. CODE ANN. 29.02(a)(1) (Vernon 1994), a person commits robbery if, in the course of committing theft and with the intent to obtain or maintain control of the property, the person intentionally, knowingly, or recklessly causes bodily injury to another. "In the course of committing a theft" means conduct that occurs in an attempt to commit, during commission, or in immediate flight after the attempt or commission of theft. TEX. PEN. CODE ANN. 29.01(1) (Vernon 1994); Autry v. State, 626 S.W.2d 758, 762 (Tex. Crim. App. 1982). The actual commission of theft is not a prerequisite to the commission of robbery. Autry v. State, 626 S.W.2d at 762. The gravamen of robbery, therefore, is its assaultive conduct and not the underlying theft. Green v. State, 840 S.W.2d 394, 401 (Tex. Crim. App. 1992) (quoting Crank v. State, 761 S.W.2d 328, 350 (Tex. Crim. App. 1988), rev'd on other grounds, Alford v. State, 866 S.W.2d 619, 624 n.8 (Tex. Crim. App. 1993)). In Cano v. State, 614 S.W.2d 578, 579 (Tex. Crim. App. 1981), the court found sufficient evidence that the defendant intentionally or knowingly caused injury to the victim by knocking her down as he took her purse. In Henry v. State, 800 S.W.2d 612, 614 (Tex. App.-Houston [14th Dist.] 1990, no pet.), the court found sufficient evidence that the defendant struck a store manager who attempted to confront him as he left the store with merchandise he had not purchased. In Candelaria v. State, 776 S.W.2d 741, 743 (Tex. App.-Corpus Christi 1989, pet. ref'd), the court found sufficient evidence that the defendant was aware that his conduct in pushing a store manager into a door while trying to flee was reasonably certain to cause the store manager bodily injury.