Putting A Shoulder To The Wheel
Considerations for Optimising Shoulder Function In All Aspects of Life
The glenohumeral joint (GHJ) has a great amount of mobility, but little (osseous) stability- unlike its counterpart in the lower limb, the hip joint. And this enhanced mobility causes it to be the most commonly dislocated joint in the human body [1].
Researchers have proposed that the evolution of the human shoulder was influenced by the necessity for improved throwing ability in hunting and defence, which required that the human shoulder joint adapted to the performance of throwing by developing a greater range of motion.
The glenoid on the scapula is relatively flat offering no osseous stability, whereas the acetabulum on the innominate has depth provide a high degree of osseous stability
But the GHJ does not work in isolation, it is part of the shoulder girdle locally and the kinetic chain, globally, and for optimal function of the GHJ we need to consider both the local system and the global system, and more importantly the functional requirements of GHJ, which needs to consider functional range of motion (ROM), functional force production and absorption, and functional stability.
Functional joint range of motion has been expressed as the minimum (ROM) necessary to perform activities of daily living comfortably and successfully [2], without pain or limitation, and excellent motor control. Although assessment of range of motion and muscle activity is easily assessed in a clinical setting, it is much more difficult to identify motor control without technical equipment such as EMG or video analysis. Nevertheless, I like to use the recommendation of Andry Vleeming and Joanne Elphinston, and look for ‘beautiful, effortless movement’ as an indication of appropriate motor control.
Functional shoulder assessment techniques are crucial to identify structural and/or biomechanical changes, and to relate them to patients’ functional limitations and disabilities, and the content of each of any assessment should be valid for the shoulder pathologies, symptoms, population-specific needs and consider age and sex [3].
When assessing someone’s shoulder function, one needs to know the functional requirements of THAT shoulder for THAT activity. It is common to see functional alterations throughout the body, which is an attempt by the person to carry out regularly repeated movements in a more economical way, and lessen the possibility of injury, across occupations, although it is more often considered within the domain of the sports person.
With this in mind, it is often stated that athletes are ‘different’ to non-athletes and therefore need to be examined differently because of this. Notwithstanding that the end stage rehabilitation will require, generally, greater force production the function of the shoulder remains the same for initial assessment. An athlete is "a person who is trained or skilled in exercises, sports, or games requiring physical strength, agility, or stamina.” (Merriam-Webster Dictionary), but one could argue that any occupational worker develops requires the same.