"As a personal trainer, it's your job to help clients achieve healthy fitness goals by recommending exercise that is appropriate to their body type and level of fitness. Interviewers may test your ability to provide fitness treatment for common injuries such as damaged rotator cuffs or sore knees. Employers will also be looking for candidates who know how to sell their services, so come prepared to discuss how you would market yourself to different kinds of clients. There are hundreds of different personal training certifications available, and the certification you choose should depend on the the position you are applying for."
If a team member is struggling to reach goal (there are monthly sales quotas), would you stay late on a shift day to help? How would you do it?
Of course I'd love to help. I'd look at what his weaknesses were, suggest they ask to shadow a team member with the trait they lack and try to emulate it when the time arrives.