If you have ever wondered how to perform a pull-up correctly, you may have read a lot of conflicting advice, with one prevalent view among trainers and coaches nowadays being that you should ‘pack’ your shoulders at the bottom of the movement (in the dead hang position), in order to promote shoulder stability.
By ‘packing’ your shoulders, these trainers mean that you should keep your shoulders down (depressed) when in a dead hang.
This however, can feel somewhat unnatural and awkward to a lot of athletes.
Looking at the two pictures below, the first one illustrates form at the bottom of a pull-up where the shoulders are allowed to rotate upwards into a dead hang position, whereas the second one shows the dead hang with the shoulders ‘packed’.
|1. Dead hang position on pull-ups|
|2. Pull-up with shoulders packed|
At first sight, the advice to ‘pack’ the shoulders can seem sound: the humerus (the bone of the upper arm) articulates with the scapula (the shoulder blade) in a socket called the glenoid cavity.
The glenoid cavity is very shallow, allowing the humerus a large range of movement, but this shallowness also makes the gleno-humeral joint structurally unstable.
The head of the humerus is held into the glenoid cavity by 4 main ligaments (gleno-humeral ligaments) which help prevent the shoulder from dislocating. In addition, 4 rotator cuff muscles also promote shoulder stability by holding the humeral head inside the glenoid cavity.
Thus, the reasoning goes, by keeping the shoulders ‘packed’ at the bottom of a pull-up, you greatly reduce the strain on the shoulder joint when in the dead hang position, and reduce the risk of dislocations.
Whilst this advice might make sense for people who have previously dislocated their shoulders, and have loose gleno-humeral ligaments or weak rotator cuffs, the problem is that it also completely ignores basic anatomical facts!
One particularity of the scapula (the shoulder blade) is that it falls within its range of movement to upwardly rotate (as illustrated below). In effect, by packing the shoulders, you are preventing this upward rotation from happening.
On top of the scapula (the shoulder blade) is a bony process called the acromion process, which extends laterally over the gleno-humeral cavity, and the head of the humerus.
Under this bony process, and attaching on the head of the humerus, lies one of the rotator cuff muscles, the supraspinatus.
The long head of the biceps tendon also runs under the acromion process in order to attach to the scapula.
By preventing the scapula to rotate upwards when ‘packing’ the shoulders at the bottom of a pull-up, you effectively reduce the space between the acromion process and the head of the humerus, often causing either the supraspinatus or the long head of the biceps tendon to become pinched between the two. This can result in a condition known as ‘shoulder impingement syndrome’, resulting in a sharp pain when lifting your arm up.
The video below illustrates the mechanics of the movement:
Thus, there is absolutely no need to keep a healthy shoulder ‘packed’: in the dead hang position, the 4 rotator cuff muscles ‘fire up’ and work together to support the gleno-humeral ligaments and maintain the stability of the humeral head inside the glenoid cavity. On the other hand, and contrary to the advice often given, ‘packing’ the shoulders often results in impingement syndrome in the long term.
Trainer Paul Zaichik illustrates the point forcibly in the video below:
I hope this post dispels some of the common myths and misconceptions of what constitutes correct pull-up form.