Hi
I 'm playing always at (dark) green condition, trying to have (synchronize) at least 90%
& green (very good/perfect) morale.
Performance is somehow irrelative to condition ( it happened to won, with good rates, a second game after 3 hours from my first game, when I didn't have the chance to log in).
Of course with low condition it's more possible to have an injury and you cannot play some formation/tactics (for example whole pitch pressure exhausting the condition of your players).
But even with perfect condition & morale, you can't avoid injuries. This is a part of the game, which as I can see, have a percent (don't know 50% ?) which is random.
About training, as I can see with "no time limit" training last period, condition also is irrelative (or meaningless) with gaining ability and injuries possibility