Young Basketball players are increasingly becoming more active which puts more stress on their bodies. An elite grade 9 Basketball player in the month of January will be having 2-4 rep practices a week, 5-7 school practices, pick up games, 2-7 team games, maybe a phys-ed class and personal training. This takes a big toll on the body!
I am not saying this is terrible however your players need to stretch before and after every game and practice (this includes pick up games). Before practice have your team do some Dynamic Stretches and after practice have your team do some static stretches.
Also encourage your players to eat healthy, greasy foods do not promote muscle growth and heart health. Have your team eat pasta a few hours before a game and something like chicken after a game.