make sure you're not hard tackling when you don't need too. for instance, i almost never hard tackle against teams that are weaker than me. If the assistant manager suggests that I tackle hard I might switch at that point, but I usually start the match in normal. Also, make sure those morals are high or you will get more injuries. the harder you play the harder you pay.

I typically only use hard tackling against higher quality teams to start the match. If I take a decisive lead I'll switch to normal tackling to avoid injuries.