Answer: action; precontemplation; action
Explanation: The stages of behavioral change exhibited in the scenario described above include the action stage which is the most obvious stage of behavioral change whereby implementation of strategy, plans, experience are put into use, being an avid tennis player he was actively preforming the sport. After this, precontemplation occurs which describes the period whereby he had a compulsory unplanned break from the sport due to injury. Then the action stage again which occurs after recovering from injury and getting back into active performance of his favored sport.