GMAT Critical Reasoning (CR) | Re: Patient: I have read that particles of my artificial hip can wear

One way to STRENGTHEN the patient's conclusion is to WEAKEN the surgeon's conclusion.
The surgeon contends that with NORMAL USE it is almost impossible for the artificial hip to have already begun to wear away.
Answer choice A: The patient has not followed the post-operative instructions she was given regarding how much time she should spend engaged in vigorous activities.
If the patient has engaged in vigorous activities -- the opposite of NORMAL