Tween Fitness (for boys 8-13) Let the Y help your tween during these crucial adolescent years learn how to grow stronger and more fit while having fun! We know that exercise helps everybody reduce anxiety and stress and improve self-esteem and that rings especially true for young people. Our certified trainer can show your tween how to make fitness and healthy habits a part of their lives forever. They will use a wide variety of equipment, including our PlayFit exergames in the Youth Center, with the focus on safety, movement, and fun!