Couldn't play all day so I minimize the number of logins.

Count the number of recovery until next match, and train the players so that when the next match start they will have 95~99% condition. For bench players I train extra so that their condition will not exceed 99% the next time I log into the game.

I don't think there is correlation between how much time have passed since last training and the player performance, nor chance of injury if the player is tired or not.