Personalized Heart Belongs To Gym Toddler 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 toddler-soft cotton tee in look-at-me, big kid colors. 4.5 oz., 100% combed ringspun cotton. White is sewn with 100% cotton thread. Topstitched rib crew neck. Double-needle stitched sleeves and bottom hem. Shoulder-to-shoulder taping.