Study Design: Repeated-measures experiment. Objective: To compare measures of end point accuracy (EPA) for 2 feedback conditions: (1) visual and kinesthetic feedback and (2) kinesthetic feedback alone, during shoulder movements, at 3 different speeds. Background: Shoulder joint kinesthesia is typically reported with EPA measures, such as constant error. Reporting multiple measures of EPA, such as variable error and absolute error, could provide a more detailed description of performance. Methods and Measures: Subjects were seated with the shoulder abducted 90° in the scapular plane and externally rotated 75°, with the forearm placed in a custom shoulder wheel. Subjects internally rotated the shoulder 27° to a target position at 48° of shoulder external rotation for both conditions. Motion analysis was used to determine peak angular velocity and 3 EPA measures for shoulder movements. Each EPA measure was compared between the 2 feedback conditions and among the 3 speeds with a separate 2-way analysis of variance. Results: Movements performed with kinesthetic feedback alone, measured by constant error (P<.01), variable error (P<.01), and absolute error (P<.01), were less accurate than movements performed with visual and kinesthetic feedback. Faster movements were less accurate when measured by constant error (P = .01) and absolute error (P<.01) than slower movements. Subjects tended to overshoot the target in the absence of visual feedback; however, movement speed played minimal role in the overshooting. Conclusions: Multiple measures of EPA, such as constant, variable, and absolute error during simple restricted shoulder movements may provide additional information regarding the evaluation of a motor performance or identify different central nervous system control mechanisms for joint kinesthesia.

J Orthop Sports Phys Ther. 2004;34(8):468-478. doi:10.2519/jospt.2004.1151 

Key Words: kinesthesia, proprioception, target accuracy, upper extremity

This case study details a rare injury managed conservatively with aggressive therapy with early return to competition. A 17-year-old high school wrestler suffered indirect trauma to the right upper extremity. The patient was forced to the mat where he felt pain in the posterior aspect of his shoulder and was point tender over the inferior pole of his right scapula. Radiographs revealed an avulsion fracture at the inferior angle of the scapula. Aggressive therapy included modalities to control inflammation and muscle guarding in addition to early scapular mobility. Maintenance of glenohumeral motion and upper extremity strengthening was started within a week. The patient was able to wrestle in the state tournament 3 weeks after initial injury. At the 6-month follow-up, the patient had no clinical tenderness, full range of motion, and no motor deficits. The outcome resulted in clinical and radiological healing of the fracture and no functional deficits.

J Orthop Sports Phys Ther. 1997;27(6):444-447.

Key Words: fracture, scapula, avulsion