I went through a 3 step process.
1) Phone interview; I was asked why I'm interested in Equinox and to briefly highlight my experience as a personal trainer.
2) Panel interview; I had a face to face with the personal training manager and the fitness director. They took turns asking about my lifestyle, details on my resume, education and experiences in previous jobs (both related & not related to the position I was applying for).
3) Group interview; Me and 3 other candidates met with the two people from the panel interview along with the general manager of the club and the fitness director from another club. They started with something they called "connecting the dots" to break the ice and asked one of the other candidates to perform 10-15 squats. Afterwards, the rest of us were asked to assess the squat. Next they asked me to perform the same amount of push-ups and asked the others to assess my push-up. For the final part of the group interview, they asked us to design a two week program for a hypothetical client and gave us 20 minutes to complete it.