How do I improve my strength and agility in FIFA 12?

I play career mode in FIFA 12 and have played 2 seasons but my character does not improve in strength and agility. What do I need to do during games to get better?

Edit: These are my conclusions for now:

• The agility and strength attributes are governed by your height and weight. The "fatter" your character, the slower he is, but his strength raises. There is a sweet spot in the height/weight ratio.
• If you play a virtual pro you can improve through accomplishments
• It is very hard but possible to improve strength/agility otherwise, but I do not know what the trigger is.

This page has a list of all the Accomplishments and the reward associated with each:

Virtual Pro Accomplishment List

From this list the following accomplishments will improve Strength or Agility:

ARENA
14) Check out the fakeshot – perform the fakeshot when inside the penalty 
box
Agility +1

24) Beat a player with skill – dribble past any opposition player or the 
goalkeeper using any skill move
Agility +1

PHYSICAL
01) Beat 2 players – dribble past two players in a single match with your 
virtual pro
Agility +2

05) Win 3 headers – win a minimum of 3 headers in any match with your pro
Strength +1

08) 2 jumping headers – win a total of 2 jumping headers in a mathc with 
your virtual pro
Strength +1

13) Win 5 games – play in & win at least 5 total matches as your virtual pro
Strength +1

19) 2 career volleys – score 2 goals from any type of volley in your career
Agility +3

24) 25 total headers won – win a total of 25 headers in the course of your
career
Strength +1

30) Win 150 tackles – win a total of 150 tacles of any type in your career
Strength +2

33) 10 matches in the rain – play through at least 10 matches in rainy 
weather conditions
Agility +3

39) Get fouled & win 50 free kicks – get fouled & win a total of 50 free 
kicks in your career
Strength +2

42) Volley in consecutive matches – score with a volley of any type in 2 
consecutive matches
Agility +4

47) Play 100 games – play in and complete 100 matches with your virtual pro
Strength +2