Personalized Heart Belongs To Gym Toddler Long Sleeve T-Shirt. My heart belongs to gym text with the word GYM wearing sneakers is a funny school design to brighten the day of teachers, students, athletes and fitness gurus. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.