There are other things that you can include on your resume besides work experience. Have you ever been on a team? Can you highlight your strengths? Are you an excellent communicator? Have you demonstrated leadership qualities in other areas of your life that will transfer well into the wellness and fitness industry. Do you have a solid understanding of the science related to personal training that you desire to use to inspire other to lead active lifestyles. Do you have a genuine desire to work and learn in the industry? Are you able to express what industry guidelines you refer to as far as designing exercise prescription is concerned. Express that on your resume particularly your objective.
Fitness professionals are dynamic, energetic individuals who love what they do. Make sure this is well-conveyed in the cover letter of your resume as well as your resume.
I wish you all the best in your search for employment.