Why is a static hang so hard?

Michael Bischoff, MT

Static hangs are a great workout
Static hanging is a quick way to tire out your arms and shoulders, and it’s a great isometric exercise that trains your endurance on the wall. So why does it take so much out of us?
To explain, we need to talk about the structure of the shoulder capsule. It’s more than the cylinder of ligaments that surround the head of the humerus. The tendons of the bicep and rotator cuff (especially supraspinatus, subscapularis, and infraspinatus) are interwoven into the ligamentous tissue. Why?
Well, when one of these tendons gets a pull, it pulls directly on the capsule. This causes a response for all the muscles around the capsule to tighten.

When a joint capsule is put into tension, all the muscles surrounding a joint tense to protect the joint.

Next, take a look at the insertion of the bicep tendon (BI), supraspinatus (SUP-T) and subscapularis (SUB-T). Note how they are all woven together. If you have your arm above your head, it’s almost a direct line for the force through the arm into the shoulder. When those three muscles tense, they are causing a lot of tension through the capsule. This is actually very good for the shoulder’s stability, as it increases negative capsular pressure in an uninjured shoulder. (If you’ve had shoulder surgery or a dislocation, you have to rely more on muscular strength).
Diagram detailing shoulder capsule attachments
So, to put this all together – when you are hanging, you are
  1. Sending your bodyweight through a few specific muscles, resulting in…
  2. A response that causes all muscles around the shoulder to tense.
Increasing the activity of these muscles are important – they allow you to climb at your best. Try incorporating a hanging exercise at the start of your climb and see for yourself.
Questions? Want to learn more? Leave a comment on this post.

References:
Wilk, Arrigo, and Andrews. Current Concepts: The Stabilizing Structures of the Glenohumeral Joint. (1997) Journal of Orthopaedic & Sports Physical Therapy.
Morag et al. MR Arthrography of RotatorInterval, Long Head of the Biceps Brachii, and Biceps Pulley of the Shoulder. (2005) Radiology; 235:21–30
Figure 1: Singh et al. (2015). Macro/micro observational studies of fibres maintaining the biceps brachii tendon in the bicipital groove: Application to surgery, pathology and kinesiology. Folia Morphologica. 74. 439-446. 10.5603/FM.2015.0105.