Come from, I see in the gym is people coming to the gym, grabbing dumbbells and coming extra rotation to the side here. One of the issues is that the rotator cuff doesn't actually cut like doesn't control external rotation under load this way but rather force needs to come through this direction pushing outwards or upwards in this direction. When you're doing it here, it's just the bicep being active as the sway back and forth. What you should do instead is grab a band just like this set up here and come through extra rotation to the side. This is how the rotator cuff is actually going to have force put onto it. Try so in your next warm up for upper body workout.