Monie, Touskasis & Allison, 2008. Joint Position Sense of the Human Shoulder

Joint Position Sense (JPS) of the shoulder as determined by repeated repositioning tasks has been performed under different constrained testing conditions. The variability in the testing protocols for JPS testing of the gleno-humeral (G-H) joint may incorporate different movement patterns, numbers of trials used to derive a specific JPS variable and range of motion. All of these aspects may play an important role in the assessment of G-H JPS testing. When using a new instrument for assessing JPS all of these issues need to be examined to document the optimal testing protocols for subsequent clinical assessments. By undertaking these minor studies future clinical trials may be more optimally assessed to determine if there are differences between dominant and non-dominant arms as well as the presence of JPS changes in performance associated with pathology and rehabilitation.

This study used a 3-dimentional tracking system to examined gleno-humeral (G-H) JPS  using 2 open kinetic chain (OKC) movement patterns. The ‘conventional’ 90 degree abducted, externally rotated movement was compared to the hypothetically more functional D2 movement pattern used in proprioceptive neuromuscular fascilitatory techniques. These two patterns were tested at different ranges (low and high). Two cohorts (n=12, n=16) of normal healthy athletic males aged 17-35 years, performed matching tasks of both left and right arms. The second cohort (n=16) were assessed with and without strapping the G-H joint with sports tape. Accuracy (overall bias) and precision (variability) scores were determined for progressively greater numbers of trials.

The findings of the study show that estimates of JPS accuracy and precision become more stable from data derived from 5 to 6 matching trials. There were no statistical differences between sides [95%CI » ± 1.5cm]. The accuracy but not precision improved as subjects approximated the ‘high’ end of range in the ‘conventional’ or D2 pattern.  Furthermore, no systematic differences were detected at different ranges of movement or movement patterns with or without the application of sports tape.

These findings provide a guide to the number of trials that optimise the testing of the G-H joint and also suggest that in normal controls the magnitude of differences between sides and movement patterns is similar. These findings also indicate that sports tape applied to the shoulder may not significantly change the JPS performance in healthy, athletic males.