If it's only the colour that's changed then it's to do with the proposed change in engine (which hasn't happended yet) and BMI. If there is a red star next to the stat, then it's maxed.

The following from FAQ might help ...

1. How does the training work?
A player needs to reach 100 points in a particular skill to gain a level/point in that skill. Once he gains a level he again starts from 0 plus training points over the 100 from the last level gain.
Each training cycle (once per week) a player gets 10 +- 2 training points automatically, he also gets points from teamwork (teamwork divided by 2), each player also gets gets training points from the coaches skill (For Example: player is training kicking, the coaches skill in kicking is 17 so the player gets additional 17 training points) and lastly he gets 4 additional points for the training hall and 4 for each consecutive training hall upgrade. He also gains/loses points depending on training intensity and players age. And that's the secret of training in Grid-Iron world.