Preventing shoulder injuries

I have two players with shoulder issues. They have been subject to the machine gym environment and fell in love with Smiths. What could I put into my dynamic warmup to encourage full range of shoulder movement.

I have been weight training for 35 yrs. Mostly selt taught and mostly incorrectly until now. As a result I don’t have full range of movement in my shoulders. I have never suffered any shoulder injury despite having played contact sport. I had never heard of a rotator cuff injury until recently. So, my quetion; ‘is the severity of these collision rotator cuff injuries lessened by the emphasis on full range of movement, or, if the shoulder is built up to maximal strength, with no regard full range of movement, will that protect the shouler from injury.