Most fitness club (especcially Lifetime) hiring managers are very discriminating, if they don't think of you as someone they would have sex with or that would boost their sales they usually will not even think of hiring you, yes they are jerks especcially this guy that interviewed you, they think they are better than everyone else and try to cut people down, don't let it get to you.
I have been a fitness trainer in Dallas, TX since the late 80's, it used to be that fitness clubs were not so discriminating, now they discriminate against, gender, race, length of hair/ hair style and especcially against age, sex and disabilities, they violate the whole discrimination laws of the EEOC,
I am degreed, have several certifications, positive attitude, very well built and still get discriminated against at Lifetime and other facilities because I am over 45.
I suggest that you get on Lifetime's job email list and apply again, record all they say, if you cannot do this over the phone ask for personal interview, find an employment attorney, file a complaint with EEOC and file a law suit against life time (for at least a years pay). they will be forced to hire you plus you will be awarded a years pay, the hiring manager will be fired and it will go on his record, he will never work in fitness clubs again. I suggest talking to an employment attorney first to find your best plan of action.
I plan on doing this also.