Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement.
ABSTRACT Treatment of patients with impingement symptoms commonly includes exercises intended to restore "normal" movement patterns. Evidence that indicates the existence of abnormal patterns in people with shoulder pain is limited. The purpose of this investigation was to analyze glenohumeral and scapulothoracic kinematics and associated scapulothoracic muscle activity in a group of subjects with symptoms of shoulder impingement relative to a group of subjects without symptoms of shoulder impingement matched for occupational exposure to overhead work.
Fifty-two subjects were recruited from a population of construction workers with routine exposure to overhead work.
Surface electromyographic data were collected from the upper and lower parts of the trapezius muscle and from the serratus anterior muscle. Electromagnetic sensors simultaneously tracked 3-dimensional motion of the trunk, scapula, and humerus during humeral elevation in the scapular plane in 3 handheld load conditions: (1) no load, (2) 2. 3-kg load, and (3) 4.6-kg load. An analysis of variance model was used to test for group and load effects for 3 phases of motion (31(-60(, 61(-90(, and 91(-120().
Relative to the group without impingement, the group with impingement showed decreased scapular upward rotation at the end of the first of the 3 phases of interest, increased anterior tipping at the end of the third phase of interest, and increased scapular medial rotation under the load conditions. At the same time, upper and lower trapezius muscle electromyographic activity increased in the group with impingement as compared with the group without impingement in the final 2 phases, although the upper trapezius muscle changes were apparent only during the 4.6-kg load condition. The serratus anterior muscle demonstrated decreased activity in the group with impingement across all loads and phases.
Scapular tipping (rotation about a medial to lateral axis) and serratus anterior muscle function are important to consider in the rehabilitation of patients with symptoms of shoulder impingement related to occupational exposure to overhead work. [Ludewig PM, Cook TM. Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement.
SourceAvailable from: Jihyun Lee
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ABSTRACT: Purpose: Scapular dyskinesia is a change in position or movement of scapula, which is highly prevalent in athletes with overhead activities. In addition to biomechanical changes in shoulder complex, neurocognitive impairments can have a significant role in its creation. Thus, this study aimed to compare neurocognitive scores between athletes with and without scapular dyskinesia. Methods: In this study, 30 athletes with overhead activities participated. Caliper and SART (Speed Anticipation and Reaction Time) sets were used for assessing subjects' scapular dyskinesia, reaction time, and anticipation skill. Results: Athletes with scapular dyskinesia had significantly a slower visual and auditory complex c hoice of reaction time, and a lower auditory choice of reaction time compared to athletes without scapular dyskinesia. Conclusion: No significant difference was seen between two groups in terms of visual choice of react i on time and anticipation skill. Thus, athletes with scapular dyskinesia had poorer performance in more complex neurocognitive tests compared to athletes without it.