I have trained pull up for about a year and I can do 1 reps of one arm pull up. However, my back is really lack of thickness compare with friends who train with me.
I see the main difference between and my friend, is that they retract their scapula in pull up top position. But for me, I cannot do that, when I do pull up mostly my back is rounded and not retracted. It seems I cannot activate my traps and rhomboids to retract.
I have winged scapula problem, one side of scapula is quite unstable, this may contribute to the problem.
How do I learn to retract scapula when I do pull up? Help would be really appreciated!