You are getting to many injuries form hard training... The only difference between hard and normal training is time... Using hard training you click it once, and using normal training you click it once and the you wait 15/30/60 minutes to click it once more. Final result is the same (you get the same range of skill progression for the same amount of condition), except your players have much more chance to get injured training hard... Btw, training any player age 30+ is waste of time, and those 26+ players wont get more than 1 quality point per season, unless they were fast trainers when young and played almost all games in the season to get 2 quality points...