One of the toughest guys I knew showed me a light rep slo-motion thing to deal with a shoulder injury and I was convinced. Eventually my focus became flexibility and that coincided with old age in a fortuitous turn of events.
When I was young I never could get the muscles I wanted. Now I'm old and glad to have pain-free flexibility. I see too many who when young had the physique I was aiming for but who now just can't move around very well.
Would you share the “...light rep slo-motion thing to deal with a shoulder injury ...” that worked for you?
Going slow. Time under tension is the key. Well, that’s what works for me.