Hope we understand what you meant by training is not working.

With the particularly quoted GK drill, it would only work on GKs, as it’s skills within the drills are only for GKs. All other outfield players do not have those skills, hence could not improve.

If you are referring to other drills on improving other attributes, the training required for improvement depends mainly on both the original market value (at the time when the player was bought from auctions or as recommended player, but not from another manager via negotiations) and the average % level of attributes relevant to the skills involved with the drill.

The former will determine how sensitive the player is to training. The higher the market value is, the more improvement the player would receive from training. And needless to say, the higher the level the drill is, the more efficient the training would be as well.

The latter will determine how much the player can improve further. Typically, a newly bought player who is close to max value, a 18% condition training (6 * hard training) should give a 4% increase in skills, and understandably the improvement level will drop when the skills go up. Take an example of an 18yo 99% FT at max value, usually improvement will slow down significantly at around 130% and even more at 140%. Any training higher than 140% would require a lot of conditions to just increase 1%.