Don't fall for the ads shouting about sport specific training. It's really about athlete-centered preparation.
It's not about playing more tournaments and more games. It's about the developing the physical abilities and fundamental movement skills essential to a variety of sports and health.
They need foundations, not hype. They need variety, not early specialization. They need to be adaptable, not pigeon-holed into a single position in a single sport.
Young people shouldn't be trained like small adult athletes. They deserve time, patience, structure and mentoring. They need to learn what it means to be an athlete and the importance of taking care of their physical health, whether or not they become professional/elite athletes.