Scapular motion is accelerated in asymptomatic individuals with dyskinesis: An observational study

Individuals with shoulder and upper extremity pathology often present with altered scapular motion. Few studies have looked at variations in scapular acceleration as a way of quantifying scapular motion. The purpose was to determine the effectiveness of wireless accelerometers for detecting changes in acceleration in individuals with scapular dyskinesis.

Twenty-seven asymptomatic college students (mean age 24 (SD ± 1.54), 65% female, 93% right handed) were visually screened for scapular dyskinesis using previously described criteria. Of the students recruited, fifteen students were determined to have scapular dyskinesis. After securing a wireless accelerometer (MyoResearch 3D DTS) on the dominate scapula, the participants performed five repetitions of standing scaption from 0 to 140°. Linear scapular accelerations along three orthogonal axes (frontal-y, transverse-z, and sagittal-x) were collected. Intraclass correlation coefficients (ICC_{3, k}) were used to determine the between day intra-rater reliability while a one-way analysis of variance was used to determine differences in acceleration between those with and without dyskinesis.

There was good between day intra-rater reliability for the average of all three axes (ICC = 0.79) and for the x and y axes (ICC > 0.78). Reliability was poor (ICC = 0.31) for the z-axis. There was a significant increase in overall acceleration of the scapula in those with dyskinesis (p = .039). There was also a significant increase in acceleration along the y-axis for those with dyskinesis (p = .003) but not for the other axes (p > .16).

Wireless accelerometers reliably quantify scapular acceleration in healthy individuals. In a healthy population with dyskinesis, the overall magnitude of scapular acceleration was greater when compared to a healthy group without dyskinesis.