BEMIDJI — In 2017, Kyle McMartin had to give up coaching varsity football. He didn’t necessarily want to. Growing up in Osceola, Wisconsin, McMartin’s life had revolved around the gridiron, playing college football for Bemidji State on the defensive line. After his playing career, coaching became one of his true passions. But with his new job as the assistant principal at Bemidji Middle School, the responsibilities between that and his position …