6th - What affects the training:
Main training and cross training are influenced by the age and height of the player.
Younger players are faster to learn and improve in skills.
Height also influences training, a short player will be quicker to grow into an "outside" skill, while a tall player is favored in learning the "inside" skills.
JS, JR, OD, HN, DR, PA are considered "outside" skills; while the "inside" ones are: IS, ID, RB, SB.
Let's also remember that when you reach a certain age, players begin to lose skill levels (around 32, perhaps later with the new changes made in Season 52).
The general training that can be selected in the "Team Training" training field (Game Shape, Free Throw, Stamina) are not affected by age.
The Stamina skill can suffer even in a young player.