I try to strengthen my rotator cuff muscles in order to prevent injuries when lifting weights. I do some internal as well as external rotation movements with an elastic band before my actual workout.
With the right arm, I can really feel the muscles in the back of my shoulder and to some degree at my shoulder blades working when performing the movement. However with the left arm, it kind of fields like my bi- and triceps are taking over and doing the main work. I don't feel the muscles of the rotator cuff working at all. Rather a burning feeling on the inside of my upper arm (kind of a burning feeling like when you do a reps on an exercise and your muscles fatigue).
Since, from what my gym buddy and I can see, I'm performing the movements exactly the same I'm guessing it's not a technique problem. Otherwise it would occur in both arms, right? I'm also trying to grip the band at the same length so the resistance is the same for both arms.
Is this a common issue? Am I doing something wrong? How can I fix this?