HS/PE1iM - Is it necessary to sit cross legged ?

I know it is optimal and has knock on benefits to other aspects of GB training, but is it necessary for a mobility exercise that targets the shoulders ?

I'm struggling with this due to a hip flexor issue.

your first question, about shoulders, no, not related to shoulders. But sitting cross legged is a fundamental action that the human body has built in. Not having this simple and basic ability makes one dis-abled in my opinion. 

Easy to learn...

I think doing this standing is great, until you get your shoulders to 180 degrees. Then you need to sit in order to lean forward. This isn't just for going past 180 if possible, but for putting more load on the traps.

Besides loading the traps more, the sitting position with the bust leading forward forces the low back in a posterior pelvic tilt position, in this way you are sure that your arms are in line with the upper back.

If you do the exercise standing your upper back would be incline to bend back, creating an arch with the lower, and would be more difficult to compensate this aspect, you should also concentrate on hold the chest in and a posterior pelvic tilt.

By doing the exercise sitting you have the two advantages of a real 180 degree arm extension and to load the traps more with the same weght.

I do these sitting on a chair, my mobility was very poor when I started so couldn't sit on the floor.

It should be performed seated.  

It can be performed standing as previously mentioned, but this will load the lower back and distract you from properly focusing on the shoulders.

Yours in Fitness,

Coach Sommer

Thanks Coach, that answers that.