Mark is a highly experienced horseman and trainer and he has designed and built Mountain Trail courses throughout North America and abroad. These are premier sites designed for clinics, shows, and training for skill levels from beginners to highly advanced riders. He and his wife, Lee Bolender, own and operate Bolender Horse Park in Washington State which houses the finest Mountain Trail course in the world. They are also the founders of the International Mountain Trail Challenge Association (IMTCA) with the purpose of promoting the sport of Mountain Trail. They administer a judging school which certifies judges in the USA, Canada and Europe for Mountain Trail and Trail Challenge. Today, the IMTCA coordinates activities, develops training protocols, and maintains regulations and certifications for Mountain Trail competition.