The band pull apart is possibly one of the most effective accessory exercises for overall shoulder health and stability. This exercise will strengthen the rear delts and the upper back including the rhomboids and traps.
the pullapart is particularity great for people who spend the majority of their day hunched over, sitting in front of a computer. Doing this one exercise will improve you posture and help with upper back pains.
The band pull apart is great for beginners, since the only equipment required for this exercise is a band, which is inexpensive and comes with many different resistance levels, so you can get one that fits your current strength level and work your way up from there.
Band pull apart also act as a great assistance exercise for your bench press. It will strengthen and stretch the rotator cuff muscles, which helps to prevent shoulder pain during and after pressing.
Move your arms in steady and controlled pace. It is easy to use momentum with this exercise, but it will make it less effective. Remember that the negative part of this exercise is just as important as the concentric part. So don't just let the band snap back together, but move your hands slowly to the starting position.
Keep the resistance light and reps high. This is a mobility exercise for shoulder and upper back health, it is not a strength builder. You should use a resistance that allows you to accomplish at least 20 reps without rest.
Turn your palms up. Turning the palms up will emphasize more on the external rotation muscles, a group of muscles in the shoulder cuff that tend to be underdeveloped for most people compared to the internal rotators.
This exercise can be used also as a warm up or as a superset in between sets of bench pressing.