The central route of persuasion emphasizes over the fact that content which is directly related to the fact and relevant is shown to the person. Then the person is more likely to persuade to the change in his or her behavior. The fact may attract the attention of the audience, may loose credibility and have a definitive argument.
Here, in the given situation, the commercial is directly related to Lachlan. As this person is experiencing pain in the knees which can be probable cause of arthritis. Thus the commercial is persuading the Lachlan centrally.
