commonly employed in modeling utilizes regression equations that couple scapulothoracic motion to humerothoracic elevation, thereby creating a relationship known as scapular rhythm. 5 , 6 Scapular rhythm represents a generic approach to the estimation of scapulothoracic orientation that is rarely used
R. Tyler Richardson, Elizabeth A. Rapp, R. Garry Quinton, Kristen F. Nicholson, Brian A. Knarr, Stephanie A. Russo, Jill S. Higginson and James G. Richards
Nichole Turner, Kristen Ferguson, Britney W. Mobley, Bryan Riemann and George Davies
Scapular strength deficits have been linked to shoulder dysfunction.
To establish normative data on the scapulothoracic musculature in normal subjects using a handheld dynamometer.
Descriptive normative data study.
172 subjects with varying levels of overhead activity.
A handheld dynamometer was used to test the upper, middle, and lower trapezius; rhomboids; and serratus anterior.
Main Outcome Measures:
A 2-factor ANOVA was performed for each of the muscles by activity level and unilateral ratio by activity-level analyses. Post hoc analysis included multiple pairwise comparisons, using the Dunn-Bonferroni correction method.
Activity level did not significantly affect the unilateral ratios: Elevation:depression was 2.5:1, upward:downward rotation was 1.5:1, and protraction:retraction was 1.25:1. A rank order from strongest to weakest was established through significant comparisons.
The unilateral ratios along with the rank order should be considered when discussing scapular rehabilitation protocols.
should include observation of the medial and inferior border of the scapulae, scapular elevation, and the smoothness of scapulothoracic joint movement during arm elevation, as well as the speed of downward rotation of the scapulae as the arm(s) return to the pendulum position. 1 The scapular dyskinesis
Se-yeon Park, Won-gyu Yoo, Hun Kwon, Dong-hyun Kim, Si-eun Lee and Mi-jin Park
Activation of the upper trapezius, lower trapezius, serratus anterior, and triceps brachii muscles was measured, while center of pressure excursion beneath the hands was simultaneously monitored, during the performance of a push-up exercise on both a stable and an unstable base of support. The activation levels of all muscles were significantly greater for the unstable support surface when compared to those for a stable support surface (p < 0.05). A negative correlation was found between activation of the serriatus anterior muscle and center of pressure excursion (r = -0.64, p < 0.05). Performance of the push-up exercise on an unstable support surface appears to elicit greater muscle activation than a standard push-up exercise performed on a stable support surface.
Kristen F. Nicholson, Stephanie A. Russo, Scott H. Kozin, Dan A. Zlotolow, Robert L. Hulbert, K. Michael Rowley and James G. Richards
Several studies have described using an acromion marker cluster for measuring scapular orientation in healthy adults performing planar motions. It is unknown whether the acromion marker cluster method will provide the same level of accuracy in children with brachial plexus birth palsy. This study compared this method to palpation for calculating scapular orientation in children with brachial plexus birth palsy performing clinically relevant movements. Scapular orientation in ten patients was determined by palpation and an acromion marker cluster in neutral and six Modified Mallet positions. RMSEs and mean relative errors were calculated. Resultant RMSEs ranged from 5.2 degrees to 21.4 degrees. The averages of the mean relative errors across all positions for each axis were 177.4% for upward/downward rotation, 865.0% for internal/external rotation, and 166.2% for anterior/posterior tilt. The acromion marker cluster method did not accurately measure scapular rotation relative to the total movement on an individual or group basis in the population. With most relative errors over 100%, the acromion marker cluster method often produced errors larger than the actual measured motion. The accuracy of the acromion marker cluster method limits its use as a clinical tool for measuring scapular kinematics on children with brachial plexus birth palsy.
Se-yeon Park and Won-gyu Yoo
The purpose of this study was to measure muscle activation during ascending and descending phases of the push-up exercise on both stable and unstable support surfaces.
Fourteen asymptomatic male amateur badminton players. During push-up exercises on stable and unstable bases, muscle activation measurements were collected with phase divisions (ascending and descending phase).
Electromyography (EMG) was utilized to measure activation of the upper trapezius (UT) and lower trapezius (LT), middle serratus anterior (MSA) and lower serratus anterior (LSA), pectoralis major (PM), and triceps brachii (TB) muscles.
An unstable support surface produced significantly greater activation of the UT, LT, LSA, and PM muscles than a stable support surface (p < 0.05). The MSA, LSA, TB, and PM muscles demonstrated greater activation during the ascending phase than the descending phase of the push-up exercise (p < 0.05).
The unstable support surface appeared to produce relatively greater activation of the LSA than that of the MSA. The descending phase of the push-up did not demonstrate a higher level of activation for any of the muscles tested.
Fernanda Assis Paes Habechian, Dayana Patricia Rosa, Melina Nevoeiro Haik and Paula Rezende Camargo
Recently, it has been suggested that sex may influence scapular kinematics. A more comprehensive analysis of the scapular kinematics in children and adults, including sex as a factor, will help to understand if differences between sexes are present since childhood. The purpose of this study was to compare scapular kinematics between sex in children and adults during elevation of the arm. One-hundred and sixteen asymptomatic adults (58 men and 58 women) and 53 children (28 boys and 25 girls) participated in the study. Three-dimensional scapular kinematics during elevation of the arm were obtained using an electromagnetic tracking device. Women had a more upwardly rotated scapula in the nondominant side (P < .05), with large effects and a more anteriorly tilted position at 60°, 90°, and 120° of arm elevation in the dominant side, and at 90° and 120° in the nondominant side (P < .05) with moderate effects when compared with men. Differences between sexes were not found in the children (P > .05). In conclusion, sex seems to influence scapular kinematics in adulthood, but not in childhood.
Bryan R. Picco, Meghan E. Vidt and Clark R. Dickerson
). Notably, male participants had more pronounced posterior tilting than females with greater elevation in all planes. It is unlikely that these results of markedly increased posterior tilt angle with greater elevation arose from use of skin-mounted markers because measured scapulothoracic tilt
Denise M. Rossi, Renan A. Resende, Gisele H. Hotta, Sérgio T. da Fonseca and Anamaria S. de Oliveira
intervention approaches are different among patients with subacromial pain syndrome, depending on the characteristic movement impairment, such as primary glenohumeral impairments or scapulothoracic movement abnormalities. 3 , 4 Recently, the “movement system diagnosis” framework has been suggested to classify
Yin-Liang Lin and Andrew Karduna
While synchronous movement of the glenohumeral and scapulothoracic joints has been emphasized in previous kinematics studies, most investigations of shoulder joint position sense have treated the shoulder complex as a single joint. The purposes of this study were to investigate the joint position sense errors of the humerothoracic, glenohumeral, and scapulothoracic joints at different elevation angles and to examine whether the errors of the glenohumeral and scapulothoracic joints contribute to the errors of the humerothoracic joint. Fifty-one subjects with healthy shoulders were recruited. Active joint position sense of the humerothoracic, glenohumeral, and scapulothoracic joints was measured at 50°, 70°, and 90° of humerothoracic elevation in the scapular plane. The results showed that while scapulothoracic joint position sense errors were not affected by target angles, there was an angle effect on humerothoracic and glenohumeral errors, with errors decreasing as the target angles approached 90° of elevation. The results of a multiple regression analysis revealed that glenohumeral errors explained most of the variance of the humerothoracic errors and that scapulothoracic errors had a weaker predictive relationship with humerothoracic errors. Therefore, it may be necessary to test scapular joint position sense separately in addition to the assessment of the overall shoulder joint position sense.