Dear Mrs. Smith,
In response to the opening you posted for Fitness Instructor, I have enclosed my resume for your review. I understand that this position requires customer service skills and experience in leading fitness programs, and I believe I have the qualifications you seek.
Having spent the past year learning how to develop sales in the business technology industry, I am now ready to return to the field of fitness—an area I have been passionate about for a long time. In my search, I am targeting positions that will use my knowledge of fitness products and training techniques and my skills in business writing, customer service, and group leadership. I would appreciate the opportunity to discuss how my skills can help you meet the challenges you face in 2017 and beyond.
I will contact you soon to explore the possibility of an interview. Thank you for your time and consideration.