Gymtrix

Sports training has begun for babies and toddlers

As a fitness coach in Grand Rapids, Michigan, Doreen Bolhuis has a passion for developing exercises for children. The younger, it seems, the better. "With the babies in our family," she said, "I start working them out in the hospital." Ms. Bolhuis turned her exercises into a company, Gymtrix, that offers a library of videos starting with training f...