David Ertl owns a fitness center in Des Moines, Iowa. He provides personal training, fitness coaching and weight loss management. He is a personal trainer with a certification from the National Strength and Conditioning Association (NSCA) which he's had since 2005. David is also a cycling coach, with a coaching certification from USA Cycling, since 2001. He is currently a Level 1 (Elite) level coach, the highest certification available. David has been a competitive cyclists since 1973 and continues to compete at the present time. He is a coach of the Des Moines Cycle Club Race Team and also the coach for the JDRF Ride to Cure Diabetes, Iowa Chapter. David coaches individual cyclists, both recreational and competitive.

The author previously worked in the crop genetics industry for 23 years as a Research Scientist and Research Director. His current occupation as personal trainer/cycling coach is a second career.