Shoulder Joint Position Sense (JPS)
Reference:Balke M et al The laser-pointer assisted angle reproduction test for evaluation of proprioceptive shoulder function in patients with instability. Arch Orthop Trauma Surg. 2011 Aug;131(8):1077-84.
Joint Position Sense (JPS) provides the body with information about its position and direction of movement in space without visual control. This is essential if you are an athlete playing competitive volleyball or you are a senior reaching up for a can on the top shelf.
JPS is provided by the Golgi tendon organs measuring muscle tension and by the muscle spindle receptors measuring lengthening of the muscles. However, JPS is likely more complex as even the skin provides information on proprioception and sends it to the central nervous system.
There are studies demonstrating that JPS is affected in individuals with shoulder instability. However when JPS is measured in research settings, complex and time consuming equipments such as reflective markers, special cameras and computer software to measure the data are needed.
As PTs we can surely appreciate the importance of shoulder proprioception assessment and training …but how do we do this without fancy computer gadgets?
Solution: The Laser-Point assisted Angle Reproduction Test (LP-ART) has been shown to be a potentially clinically applicable test showing some validity.