Tsun-Shun Huang

Specific kinematics and associated muscle activation in individuals with scapular dyskinesis.

BACKGROUND Knowledge of the kinematics and associated muscular activity in individuals with scapular dyskinesis may provide insight into the injury mechanism and inform the planning of treatment strategies. We investigated scapular kinematics and associated muscular activation during arm movements in individuals with scapular dyskinesis. METHODS A visual-based palpation method was used to evaluate 82 participants with unilateral shoulder pain. Scapular movements during arm raising/lowering movements were classified as abnormal single pattern (inferior angle prominence, pattern I; medial border prominence, pattern II; excessive/inadequate scapular elevation or upward rotation, pattern III), abnormal mixed patterns, or normal pattern (pattern IV). Scapular kinematics and associated muscular activation were assessed with an electromagnetic motion-capturing system and surface electromyography. RESULTS More scapular internal rotation was found in pattern II subjects (4°, P = .009) and mixed pattern I and II subjects (4°, P = .023) than in control subjects during arm lowering. Scapular posterior tipping (3°, P = .028) was less in pattern I subjects during arm lowering. Higher upper trapezius activity (14%, P = .01) was found in pattern II subjects during arm lowering. In addition, lower trapezius (5%, P = .025) and serratus anterior activity (10%, P = .004) were less in mixed pattern I and II subjects during arm lowering. CONCLUSIONS Specific alterations of scapular muscular activation and kinematics were found in different patterns of scapular dyskinesis. The findings also validated the use of a comprehensive classification test to assess scapular dyskinesis, especially in the lowering phase of arm elevation.

Comprehensive classification test of scapular dyskinesis: A reliability study

BACKGROUND Assessment of scapular dyskinesis (SD) is of clinical interest, as SD is believed to be related to shoulder pathology. However, no clinical assessment with sufficient reliability to identify SD and provide treatment strategies is available. OBJECTIVES The purpose of this study was to investigate the reliability of the comprehensive SD classification method. DESIGN Cross-sectional reliability study. METHOD Sixty subjects with unilateral shoulder pain were evaluated by two independent physiotherapists with a visual-based palpation method. SD was classified as single abnormal scapular pattern [inferior angle (pattern I), medial border (pattern II), superior border of scapula prominence or abnormal scapulohumeral rhythm (pattern III)], a mixture of the above abnormal scapular patterns, or normal pattern (pattern IV). The assessment of SD was evaluated as subjects performed bilateral arm raising/lowering movements with a weighted load in the scapular plane. Percentage of agreement and kappa coefficients were calculated to determine reliability. RESULTS Agreement between the 2 independent physiotherapists was 83% (50/60, 6 subjects as pattern III and 44 subjects as pattern IV) in the raising phase and 68% (41/60, 5 subjects as pattern I, 12 subjects as pattern II, 12 subjects as pattern IV, 12 subjects as mixed patterns I and II) in the lowering phase. The kappa coefficients were 0.49-0.64. CONCLUSIONS We concluded that the visual-based palpation classification method for SD had moderate to substantial inter-rater reliability. The appearance of different types of SD was more pronounced in the lowering phase than in the raising phase of arm movements.

Relationship between trapezius muscle activity and typing speed: taping effect

Clinically, over-activation of upper trapezius (UT) muscular activity is a common cause of symptoms in computer users. The purpose of this study was to investigate the correlation between trapezius muscular activity and typing speed with and without taping. Twelve participants performed a typing task for 15 min with and without taping on the UT muscle. Electromyography (EMG) of the muscular activity of UT and lower trapezius (LT) was recorded. With or without taping, there was a significantly positive correlation (r = 0.40, p = 0.04) between typing speed and UT/LT. Additionally, UT and UT/LT ratios were lower with taping than without taping (difference = 5.2% and 26.9%). The LT ratio was higher with taping than without taping (difference = 5.8%). Taping can alter the muscular activity of the trapezius during typing and may have the potential to be applied in computer users to prevent over-activation of UT muscular activity. Practitioner Summary: The effect of taping was tested on typing speed and trapezius muscular activity. With or without taping, typing speed was correlated with trapezius activity. The muscle activity of the trapezius, however, was lower with taping than without taping. Thus, taping has the potential to prevent over-activation of UT muscular activity during typing.

Comparison of Aggressive and Traditional Postoperative Rehabilitation Protocol after Rotator Cuff Repair: A Meta-analysis

Introduction: In addition to size/location of tear, surgical technique, and fixation methods, a well-programmed rehabilitation protocol is also critical to successful tendon healing and satisfactory shoulder functional outcome for patients with rotator cuff repair (RCR). To date, the progression of rehabilitation is still debated. Purpose: The aim of this meta-analysis is to analyze the effects of a post-operative aggressive protocol versus those of a traditional rehabilitation protocol. Methods: We searched the database of PubMed, Ovid MEDLINE, CINAHL, Cochrane library, and CEPS and finally included 6 articles that met our selection criteria. Results: The aggressive postoperative rehabilitation protocol results in more improvement in ROM and shoulder function than the traditional protocol, but it also entails a greater risk of un-healing or re-tearing of the rotator cuff tendon. Conclusion: Although the aggressive postoperative rehabilitation protocol has positive effects for patients with RCR, factors influencing the risk of un-healing/re-tearing of the tendon should be further investigated. These factors are important to consider in the design of a post-operative program for patients with RCR.

Movement Pattern of Scapular Dyskinesis in Symptomatic Overhead Athletes

This study investigated the characteristics of arm elevation via principal component analysis in symptomatic overhead athletes with scapular dyskinesis. One hundred-thirty-four overhead athletes with scapular dyskinesis [24: inferior angle prominence (pattern I); 46: medial border prominence (pattern II), 64: pattern I + II] were evaluated by three-dimensional electromagnetic motion and electromyography to record the scapular kinematics (upward rotation/posterior tipping/exterior rotation) and muscle activation (upper trapezius: UT; middle trapezius: MT; lower trapezius: LT; serratus anterior: SA) during lowering phase of arm elevation. The results showed: (1) for pattern I and II, the first 3 principal component (PCs) explained 41.4% and 42.6% of total variance of movement; (2) the first PCs were correlated with MT, LT activity (r = 0.41~0.61) and upward rotation, posterior tipping (r = −0.59~−0.33) in pattern I, and UT, MT, SA (r = 0.30~0.70) activity in pattern II; (3) contour plots of muscle activity demonstrated that muscle activities varied with dyskinesis patterns. In summary, for the pattern I, the major characteristics are coactivation of MT and LT and corresponding scapular posterior tipping and upward rotation. For the pattern II, the major characteristics are coactivation of UT, MT and SA without corresponding scapular external rotation.

Shoulder physical activity, functional disability and task difficulties in patients with stiff shoulders: Interpretation from RT3 accelerator

We determined whether the degree of symptom-related functional disability was related to daily physical activity of the shoulder in subjects with stiff shoulders (SSs). Responsiveness and a clinically meaningful level of discrimination between improvement and non-improvement for shoulder physical activity (SPA) were determined. Twenty-six subjects with SSs participated. Shoulder physical activity was assessed by RT3 accelerometers fixed on the humerus during daily 14-h data collection periods twice a week for 2 weeks. A moderate correlation coefficient was found between SPA and functional disability (β = .47). Based on our cohort design and sample, we suggest that SPA (higher than 101.8 counts, hard-moderate or hard tasks) during daily activity are associated with (with at least 83% probability) non-improvement in an individual with SS. Compared to the non-improvement group, the improvement group had less duration of sedentary activity, less frequency and duration of hard tasks, and more frequency and duration of easy tasks (p < 0.01). Appropriate guidance on shoulder physical activities for subjects with SS is important to consider in rehabilitation strategies for these subjects. In our sample, a hard level of shoulder physical activity and sedentary activity should be cautious for these subjects. Further study is needed to validate therapeutic effect of physical activity on the course of patient improvement in subjects with SSs.

Progressive conscious control of scapular orientation with video feedback has improvement in muscle balance ratio in patients with scapular dyskinesis: a randomized controlled trial

BACKGROUND Video feedback (VF) can guide patients to consciously control scapular orientation without inappropriate substitution. This study investigated whether progressive conscious control with VF improves scapular muscle activation and movements during arm elevation in patients with subacromial impingement and scapular dyskinesis. METHODS The study recruited 38 amateur overhead athletes with subacromial impingement and scapular medial border prominence who were randomly assigned to the VF or control group. The participants in both groups controlled the scapular position and progressively practiced from 0° to 45° and from 0° to 90° of arm elevation. Participants in the VF group also controlled the scapular position with a video presentation of the scapula on a screen. We investigated the scapular kinematics, muscle activation, and balance ratio for outcome collection in the preintervention and postintervention conditions with and without VF conditions. RESULTS Decreased upper trapezius (UT) activation (3%-13%, P < .0083), increased lower trapezius (LT) activation (3%-17%, P < .0083), restored UT/LT ratios (0.67-3.13, P < .0083), and decreased scapular internal rotation (1.8°-6.1°, P < .003) relative to the preintervention condition were demonstrated in the 2 postintervention conditions in both groups. The VF group also demonstrated decreased UT/serratus anterior ratios (0.21-0.30, P < .0083) in 2 postintervention conditions relative to the preintervention condition. CONCLUSIONS The progressive control of scapular orientation with or without VF can be used to reduce the UT/LT ratio and improve scapular internal rotation during arm elevation. Control training with VF can further decrease the UT/serratus anterior ratio.