Hi guys, Can anyone help me out with this?

I've got a player that I've had from level 1, I'm now level 6. I've power trained him since day 1 but now he's got to a point where Attack and Physical wont increase.

Defence 34.4
Attack 54.2
Physical 54.2

Quality 47

Do I have to improve his Defensive skills to be able to increase the others?