Humans are unique amongst the apes; the bipedalism, the brain size, tool use, abstract thought, but we share the same evolutionary pathway in the early stages. We have evolved uniquely complex shoulder joints that allow us to hang from trees like Apes but also gave us the ability to catch and throw. There are not many creatures that can throw missiles like humans, we maybe horribly weak compared to our ape ancestors, but we can throw rocks and spears that can injure prey animals at a distance. This special ability comes at a cost, the arm and hand are incredibly mobile but they are also unstable and it is this instability that predisposes many of the shoulder injuries that we suffer from.
Orthopaedic surgeon Dr. John M. Kirsch, conducted research through a series of CT scans performed in 2004 to study the mechanics of the hanging exercise in the shoulders of live subjects. The study found that this simple exercise called relaxed hanging aka ‘brachial hanging’ was helpful in certain shoulder problems. The idea is that when the arm is fully overhead (in flexion), the upper arm bone (humerus) will press against the acromion (tip of the shoulder blade) and eventually reshape it. Hanging also stretches and strengthens the supraspinatus tendon. Supraspinatus tendon is particularly responsible for shoulder stability and strength.
All of us should consider introducing brachiation or hanging as part of a healthy lifestyle. To do this we need something to hang from, trees are great in summer but pull-up bars and or rings are less weather dependent.
Start by hanging straight armed for 10 seconds, count to ten slowly as you hang, take a ten second break then repeat three times. If you struggle you can rest your legs on a chair. No need to push to failure or overload just repeat these 3 sets at frequent occasions throughout the day. After a week increase to 15 seconds etc. Aim for a hang time of 2-3 minutes.