RC/PE14 and Acromial Architecture

It's treated as common knowledge in bodybuilding circles that behind the neck pull-ups should be avoided and are famous for producing injury. I thought this was a myth until I stumbled upon some information that it related to the shape of one's acromion. In other words, some people were just predisposed to injury during this movement because of the architecture of their scapulae. Is this true? If so, why is it a necessary requirement for RC? Or is it simply one of those exercises that break the inflexible and build the mobile?

I'm completely clueless on the subject, so I'd appreciate any discussion this starts 

People who are predisposed are those who have altered shoulder joint proportion for genetic problem. those people are a % of population close to zero. I had at least 1 hundred of clients, nobody has this problem. the truth is that only a little % has the required mobility to do safety the behind the back pullup. same thing could be said for behind the back military press.

Also if 100% of people in the gym wills say that normal military press is the king of exercise this is wrong because you are using a different trajectory that involves more the chest. the real shoulders exercise is military press behind the back. how many people can do bodyweigth military behind the back? I can do that but how much mobility i've built up in my shoulders girdle in the previous year.

Unbalanced shoulders and altered kinematic due to bad mobility lead to different lines of force where strength is expressed. this is a predisposition to the injury.

Who is not predisposed to injury? kids kids and kids. why? rarely they have altered shoulders kinematic. it is not the exercise itself that predispose to injury but rather an altered joint submitted to a certain exercise.

Bodybuilders have not done the preparation that you have. If you been doing the correct Foundation progressions and H1 shoulder mobility this exercise is no problem.

If you are like most bodybuilders that have extremely tight pecs and thoracic spines that don't extend then this exercise will destroy the shoulders.

That's what I had initially assumed; that it was simply an injury that resulted from improper mobility. However, I have read that this is not true, and the issue does in fact stem from acromial shape (which is of course, genetic). If you have the 'wrong' acromion type, your mobility can be peak/elite and you will still suffer from shoulder injuries by performing behind-the-neck motions.

Mercurium said:

... If you have the 'wrong' acromion type, your mobility can be peak/elite and you will still suffer from shoulder injuries by performing behind-the-neck motions ...

Which almost certainly does not apply to you.

Correct your mobility and move on.

Yours in Fitness,

Coach Sommer

But if mobility is not the issue, it's acromion-type, then I should never do them regardless of my mobility levels... Because they're 'unhealthy for my scapular type' (assuming that the acromial architecture claim is legitimate).

So are you saying that you are experiencing pain while attempting this exercise? Or are you worried about long-term effects?

Mmm... this week I have started with behind the neck pull ups and supraspinatus flared up the day after.

I am really upset because I felt I was improving quite well with shoulder mobility and strength so far. It looks like it's not enough for this progression yet.

What am I suppose to do with RC? Skip the behind the neck pull ups for now or hold to the previous progression while working on mobility?

Probably your shoulders are not prepared for them. on healthy shoulders pressing and pulling behind the back does not produce injury. my suggestion is having a check with a PT for possible shoulders limitation. meanwhile do not perform behind the back work. stay on previous exercises.

The issue is then how to understand when and if my shoulders could ever be ready for behind the back exercises.

That's rather tricky, since I have closed 4x3r behind the neck pull ups without any problem on Thursday and pain showed up only on Saturday.

Honestly I am not sure I will give it a try again.

As mentioned, PT should be able to tell you more.