I even have many injuries with the standard training (which is set to rather a low workload) so I don't really think it coz of this training, it's more likely to be the game's fault.
And like Tug said in his post, it's possible that striker lose points at marking and tackling coz those are defensive attributes and they don't train on that.
@ Equii, just to make sure, you've installed the patch right? Coz without the patch the attributes of your players will drop whatever training you use... | 
