During an interview process with applicants, an employer should avoid asking questions about the applicant’s personal characteristics.
For example, the employer is not going to want to ask questions about the applicant’s religion, whether or not the applicant has a disability, or whether or not the applicant has any other kind of characteristic that could result in some kind of a discrimination claim.
The better way to frame the question is going to be, for example, look at the essential functions of this job and find out if the applicant can perform those essential functions of the job.
For example, can the applicant lift 20 pounds? Or, can the applicant stand for a certain amount of time or sit for a certain amount of time? Instead of asking about a disability.