File
Han J1,2, Adams R2, Waddington G2, El-Ansary D3,4
1Shanghai University of Sport, Shanghai, China, 2University of Canberra, Canberra, Australia, 3Swinburne University of Technology, Melbourne, Australia, 4University of Melbourne, Melbourne, Australia
Background: To control precise movements at the shoulder, the brain has to use the proprioceptive information available from the shoulder muscles, tendons and joint capsular ligaments. Most previous studies on shoulder proprioception have focused on end of range of flexion and external rotation movements.
Purpose: To explore shoulder proprioception at the initial ranges of flexion, abduction and extension.
Methods: A cross-sectional study was conducted to assess shoulder proprioceptive movement discrimination sensitivity in 3 directions within the sagittal and coronal planes. Eighteen healthy young participants without upper limb or spinal injuries in the past 6 months volunteered (10M, 8F mean 21.9 years of age, range 18-25). Proprioception of the right dominant shoulder was measured in standing by using a purpose-built shoulder active movement extent discrimination apparatus (S-AMEDA). Participants were asked to discriminate, over a series of randomly-presented trials, between 5 possible shoulder active movement extents (26, 27, 28, 29, and 30 degrees) in flexion, abduction and extension, respectively. Order of testing flexion, abduction or extension was also randomised. The mean pair-wise Area Under the ROC Curve (AUCs) were calculated using SPSS to give each participant a proprioceptive movement discrimination score for each testing direction. A 3X2 repeated measures ANOVA was conducted to examine the direction and gender effects. Pearson's correlation was calculated to determine the relationship among proprioceptive scores of each movement direction.
Results: The mean±SD AUC proprioceptive movement discrimination scores for flexion, abduction and extension were 0.666±0.069, 0.692±0.039, and 0.620±0.104, respectively. There was a significant main effect of direction (F=4.45, p=0.020), but no interaction effect of direction and gender. Post hoc analysis showed that shoulder proprioceptive sensitivity in abduction was significantly superior to that of extension alone or the average score of flexion and extension (p=0.019, 95%CI=0.014-0.131; and p=0.023, 95%CI=0.008-0.092, respectively). There was no significant correlation among the AUC scores for each direction (all r 0.37 p>0.13).
Conclusion(s): In this study we found that shoulder proprioception at the initial range (within 30 degrees) of abduction was the most accurate, suggesting that supraspinatus may play a unique and significant role in shoulder proprioceptive function as supported by the proprioceptive receptors within the muscle. Further, unlike the ankle, where proprioceptive acuity scores for plantarflexion and inversion movement directions are significantly correlated (DeJong et al, 2005), proprioceptive acuity scores for different shoulder movement directions were not, suggesting greater component independence at the shoulder.
Implications: Although clinically supraspinatus injury may be not associated with pain, it may cause proprioceptive impairment, which needs to be addressed in a physiotherapy management program. In addition the finding that no correlation among AUC scores of each movement direction implies that physiotherapy program targeting shoulder proprioceptive control should be direction-specific.
Keywords: shoulder, rotator cuff, proprioception
Funding acknowledgements: Shanghai “Shuguang Program” (16SG45) and Chinese National Natural Science Foundation (31870936).
Purpose: To explore shoulder proprioception at the initial ranges of flexion, abduction and extension.
Methods: A cross-sectional study was conducted to assess shoulder proprioceptive movement discrimination sensitivity in 3 directions within the sagittal and coronal planes. Eighteen healthy young participants without upper limb or spinal injuries in the past 6 months volunteered (10M, 8F mean 21.9 years of age, range 18-25). Proprioception of the right dominant shoulder was measured in standing by using a purpose-built shoulder active movement extent discrimination apparatus (S-AMEDA). Participants were asked to discriminate, over a series of randomly-presented trials, between 5 possible shoulder active movement extents (26, 27, 28, 29, and 30 degrees) in flexion, abduction and extension, respectively. Order of testing flexion, abduction or extension was also randomised. The mean pair-wise Area Under the ROC Curve (AUCs) were calculated using SPSS to give each participant a proprioceptive movement discrimination score for each testing direction. A 3X2 repeated measures ANOVA was conducted to examine the direction and gender effects. Pearson's correlation was calculated to determine the relationship among proprioceptive scores of each movement direction.
Results: The mean±SD AUC proprioceptive movement discrimination scores for flexion, abduction and extension were 0.666±0.069, 0.692±0.039, and 0.620±0.104, respectively. There was a significant main effect of direction (F=4.45, p=0.020), but no interaction effect of direction and gender. Post hoc analysis showed that shoulder proprioceptive sensitivity in abduction was significantly superior to that of extension alone or the average score of flexion and extension (p=0.019, 95%CI=0.014-0.131; and p=0.023, 95%CI=0.008-0.092, respectively). There was no significant correlation among the AUC scores for each direction (all r 0.37 p>0.13).
Conclusion(s): In this study we found that shoulder proprioception at the initial range (within 30 degrees) of abduction was the most accurate, suggesting that supraspinatus may play a unique and significant role in shoulder proprioceptive function as supported by the proprioceptive receptors within the muscle. Further, unlike the ankle, where proprioceptive acuity scores for plantarflexion and inversion movement directions are significantly correlated (DeJong et al, 2005), proprioceptive acuity scores for different shoulder movement directions were not, suggesting greater component independence at the shoulder.
Implications: Although clinically supraspinatus injury may be not associated with pain, it may cause proprioceptive impairment, which needs to be addressed in a physiotherapy management program. In addition the finding that no correlation among AUC scores of each movement direction implies that physiotherapy program targeting shoulder proprioceptive control should be direction-specific.
Keywords: shoulder, rotator cuff, proprioception
Funding acknowledgements: Shanghai “Shuguang Program” (16SG45) and Chinese National Natural Science Foundation (31870936).
Topic: Musculoskeletal: upper limb
Ethics approval required: Yes
Institution: University of Canberra
Ethics committee: Committee for Ethics in Human Research
Ethics number: CEHR 10-110
All authors, affiliations and abstracts have been published as submitted.
