I have a query regarding arm flexibility. Please refer to the picture attached. As you can see, the person is not able to cross stretch and touch the arms behind the back. How can we fix this issue?
The first thing to recognise is that our mobility in this exercise is governed by two distinct movements: the overhead reach behind the neck, and the underhand reach behind the back. And our mobility is therefore limited by two distinct sets of muscles.
The overhead reach is less commonly the greater limiting factor, being restricted primarily by the elbow extensors (triceps brachii), the shoulder extensors (pectoralis major, latissimus dorsi, and teres major), shoulder girdle protractors (particularly the pectoralis minor)—as well as the glenohumeral joint capsule itself.
The underhand reach is more commonly the cause of difficulty in linking the hands, as it is for the individual in the images posted. (Notice that the arm in the overhanded position is in a very similar position in each photo, whilst the right arm in the first photo is significantly abducted and shoulder slightly protracted.) The source of the restriction is most commonly the supraspinatus, whose primary role is to stabilise the head of the humerus in the glenoid cavity during arm movement, and which passes through a small gap known as the subacromial space. The supraspinatus is consequently susceptible to impingement, injury, and hence scarring.
Regardless of the cause, the solution is identical: stretching. And two distinct stretches, corresponding with the overhead and underhand movements, can both be performed using any vertical pole that is narrow enough to grip comfortably (e.g. the frame of a machine in the gym). Try these:
Overhead stretch: Stand with your back to the pole. Bend your knees slightly to lower your weight. Reach overhead behind your neck, and grip the pole as you would a hammer. Gently stand up until you feel a strong stretch in the structures of the arm and shoulder.
Underhand stretch: Standing in the same position, with your back to the pole, tiptoe to raise your body. Reach underhand and grip the pole as you would a hammer. Gently lower your weight until you feel a strong stretch in the structures of the shoulder.
You can encourage reciprocal inhibition by actively trying to force your elbow and shoulder backward, whether overhead or underhand. And you further increase the intensity of the stretch by leaning away from the pole. As with all stretches, the three key criteria to increase mobility are time, tension, and temperature. The longer and stronger the stretch, and the warmer the environment, the more rapidly your mobility will improve.
I hope that helps.
Many exercises such as upright row cause painful injuries on the shoulders due to poor shoulder mobility.
However this test of mobility you showed in the pictures doesn't require just good shoulders but also good thoracic mobility.
I'm across the internet therefore I can not know if the problem is shoulder is thoracic mobility.
I can only suggest to improve both with front squats for the thorax and face pulls for the shoulder girdle