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.
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ABSTRACT: The benefits of progressive resistance training (PRT) among the older adults are evident, especially in the prevention of sarcopenia and improving muscle strength, which reverse the age-related loss of functional ability. However, PRT carries some risk, particularly when participants are older adults with a certain degree of muscle weakness. The purpose of this article is to discuss the PRT-related injuries, and present an overview of documented shoulder injuries among the elderly, discerning possible mechanisms of injury and risk factors. A literature search was conducted in the PUBMED database to identify the relevant literature using combinations of keywords: strength-training injuries, resistance-training injuries, sports injuries in the elderly, shoulder complex, shoulder injury, and shoulder disorder. Acute and chronic injuries attributed to PRT have been cited in the epidemiological literature. The shoulder complex, has been alluded to as one of the most prevalent regions of injury, particularly in exercises that place the arm extended above the head and posterior to the trunk. However, the risk for injuries appears to be higher for testing than for training itself. One-repetition maximum strength testing may result in a greater injury risk. This technique, though acceptable, needs additional precautions in inexperience older adults to prevent injury. Thus, the best treatment for PRT age-related injuries is prevention. Appropriate and individualized training programs, the use of safe equipment, careful warming up and cooling down, correct range of motion, progressive intensity training, cardiovascular and musculoskeletal fitness are essential aspects of injury prevention among the elderly.Aging - Clinical and Experimental Research 05/2014; 26(3):235-240. · 1.01 Impact Factor
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ABSTRACT: Shoulder injuries in the thrower can prove a challenge to diagnose and treat. Overhead throwing is an intricate motion that places considerable torque on the shoulder. The complex interplay of the scapula with the glenohumeral joint and its surrounding musculature allows elite pitchers to achieve speeds >95 miles per hour. An understanding of scapular motion is integral to diagnose and treat shoulder pathology in these athletes. Treatment is aimed at addressing the underlying cause with a physical rehabilitation program. Although nonoperative care is the most predictable and useful treatment, occasionally operative treatment is necessary. This chapter will outline normal scapular motion during throwing, the effects of common shoulder disorders on throwing mechanics, and the prevention, diagnosis, and treatment of these conditions.Sports medicine and arthroscopy review 06/2014; 22(2):80-87. · 1.16 Impact Factor
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ABSTRACT: A total of 11 male and 19 female violinists performed 30-second random-ordered slow and fast musical repertoire while right shoulder three-dimensional kinematic, and upper trapezius and serratus anterior surface electromyography (EMG) data were summarised using exposure variation analysis (EVA), a bivariate distribution of work time spent at categories of signal amplitude, and duration spent at a fixed category of amplitude. Sixty-two per cent of intraclass correlation coefficients [1,1] for all kinematic and EMG variables exceeded 0.75, and 40% of standard error of the measurement results were below 5%, confirming EVA reliability. When fast repertoire was played, increases in odds ratios in short duration cells were seen in 23 of 24 possible instances, and decreases in longer duration cells were seen in 17 instances in all EVA arrays using multinomial logistic regression with random effects, confirming a shift towards shorter duration. A reliable technique to assess right shoulder kinematic and EMG exposure in violinists was identified.Ergonomics 04/2014; · 1.67 Impact Factor