Why Workers Hesitate to Report Their Work-Related Musculoskeletal Symptoms: A Survey at a Korean Semiconductor Company.

Underreporting work-related musculoskeletal disorders (WRMSD) has been an issue in South Korea. The purpose of this survey was to figure out how many employees of a semiconductor and liquid crystal display company in South Korea experience WRMSDs and what the possible obstacles in reporting to the company are. A survey was developed with demographic questions, perceived WRMSD symptoms, and reasons for reporting or not reporting WRMSD. The survey was distributed via the company's intranet to all employees (24,380) whose employee identification number ended with an odd number. A total of 2862 employees completed the survey and the response rate was 11.7%. A total of 55.2% of respondents had felt at least one musculoskeletal symptom during the past year. More than 40% of workers who had experienced pain or discomfort during the past year thought their symptoms were more than 50%. work-related. More than one-fourth of respondents answered that they did not report their symptoms to the company more than once. The open-ended answers for not reporting WRMSD were categorized into seven common reasons. The reasons for not reporting WRMSD in previous studies show a combination of personal, organizational, socioeconomical, and cultural factors. To encourage and manage WRMSD effectively, seven recommendations of authors are described.

Stretching position can affect levator scapular muscle activity, length, and cervical range of motion in people with a shortened levator scapulae.

OBJECTIVES: Levator scapulae (LS) muscle stretching exercises are a common method of lengthening a shortened muscle; however, the appropriate stretching position for lengthening the LS in people with a shortened LS remains unclear. The purpose of this study was to compare the effects of different stretching exercise positions on the LS and introduce effective stretching exercise methods to clinicians. PARTICIPANTS: Twenty-four university students (12 men, 12 women) with a shortened LS were recruited. METHODS: LS muscle activity, LS index (LSI), and cervical range of motion (ROM) were measured pre (baseline) and post three different stretching exercise positions (sitting, quadruped, and prone). RESULTS: The LSI and cervical ROM exceeded the minimal detectable change and had significant changes. The LSI was greater in the sitting position than at the baseline (p = 0.01), quadruped position (p < 0.01); the LSI in the prone position presented a higher increase than the quadruped position (p = 0.01). The cervical ROM increased in the sitting position when compared to the baseline (p < 0.01) and quadruped position (p < 0.01). CONCLUSIONS: Stretching the LS in the sitting position was the most effective exercise for improving LS muscle length and cervical ROM.

Changes in gait kinematics and muscle activity in stroke patients wearing various arm slings.

Stroke patients often use various arm slings, but the effects of different slings on the joint kinematics and muscle activity of the arm in the gait have not been investigated. The effects of joint kinematics and muscle activity in the gait were investigated to provide suggestions for gait training for stroke patients. In all, 10 chronic stroke patients were voluntarily recruited. An eight-camera three-dimensional motion analysis system was used to measure joint kinematics while walking; simultaneously, electromyography data were collected for the anterior and posterior deltoids and latissimus dorsi. The amplitude of pelvic rotation on the less-affected side differed significantly among the different arm slings (P<0.05). Changes in the knee kinematics of the less-affected side also differed significantly (P<0.05), while there were no significant differences in the muscle activity of the affected arm. In stroke patients, an extended arm sling is more useful than no sling or a flexed arm sling in terms of the amplitude of the rotation of the less-affected pelvic side in the stance phase while walking. The less-affected knee joint is flexed more without a sling than with any sling. All arm slings support the extension of the contralateral knee.

Foot exercise and taping in patients with patellofemoral pain and pronated foot.

This study compared the effect of three foot conditions (untreated, short foot [SF] exercise, and Tape) on knee and ankle muscle activity during forward descending of stairs in subjects with patellofemoral pain syndrome (PFPS) and a pronated foot. Surface electromyography activities in the vastus medialis oblique (VMO), vastus lateralis (VL), and abductor hallucis (AbdH) were recorded during forward descending stairs; Surface electromyography data were expressed as percentages of the maximal voluntary isometric contraction. A total of 18 subjects (6 males and 12 females) with PFPS and a pronated foot participated in the current study. The SF exercise was associated with significantly greater AbdH muscle activity compared to the tape condition during forward descending stairs. However, there was no significant difference in VMO or VL muscle activity, or in the VMO/VL muscle activity ratio, among the three foot conditions. The SF exercise was the most effective method of increasing AbdH muscle activity during forward descending stairs in subjects with PFPS and a pronated foot.

The effect of load weight vs. pace on muscle recruitment during lifting.

The purpose of this study was to compare the effect on the trunk and upper extremity muscle recruitment when controlling the lifting pace and the lifting weight. Thirty nine healthy subjects performed a total of 12 lifts (3 lifting trials per condition, 2 lifting weights, and 2 lifting paces), from waist height to shoulder height. Kinematics of upper extremity and the box and electromyography of trunk and upper extremity muscles were collected. Temporal muscle recruitment pattern varied between muscles based on their function. Heavier lifting weight evenly increased the muscle recruitment throughout the lifting period without changing their temporal pattern. In contrary, lifting pace affected the temporal recruitment pattern in most of muscles. The faster lifting pace increased the muscle recruitment at the beginning phase but decreased at the terminal phase of lifting. It is important to educate the workers about the effect of lifting pace and weight on the biomechanical load to control the mechanical load on the muscles and spine.

The effect of a new syringe design on the ability of rheumatoid arthritis patients to inject a biological medication.

Self-administration of new biological medications can be difficult for Rheumatoid Arthritis patients with functional impairment and hand and dexterity limitation. Twenty-three Rheumatoid Arthritis (RA) patients participated in this study to compare preferences and injection forces using a conventional syringe and a new ergonomically designed syringe. Injection force measurements were collected in two ways: a) isometric forces, with the syringes' plungers in fixed positions (depressed halfway and fully depressed), and b) forces exerted during injection of the medication. Subjects' grip and pinch strengths were measured. A perception questionnaire gauged subjects' impressions and preferences. Subjects were capable of exerting significantly higher isometric forces using the new syringe with the plunger fixed both halfway and fully depressed. During injection of the medication, peak and mean injection forces were significantly higher, and duration was shorter, when using the new syringe. Subjects rated the new syringe higher on all twenty attributes on preference and performance. Therefore, it is expected that the new syringe will benefit self-administration of medication injection for RA patients.

Kinematic analysis of dynamic shoulder motion in patients with reverse total shoulder arthroplasty.

BACKGROUND: Reverse total shoulder arthroplasty (rTSA) has been used to treat patients with irreparable rotator cuff dysfunction. Despite the proven clinical efficacy, there is minimal information regarding the underlying changes to the shoulder kinematics associated with this construct. Therefore, we sought to examine the kinematics of dynamic shoulder motion in patients with well-functioning rTSA. METHODS: We tested 12 healthy subjects and 17 patients with rTSA. All rTSA patients were able to elevate their arms to at least 90° and received the implant as the primary arthroplasty at least 6 months before testing. On average, the rTSA patients elevated their arms to 112° ± 12° (mean ± SD) and reported an American Shoulder and Elbow Surgeons outcome score of 90.6 ± 6.3. A 3-dimensional electromagnetic motion capture device was used to detect the dynamic motion of the trunk, scapula, and humerus during bilateral active shoulder elevation along the sagittal, scapular, and coronal planes. RESULTS: In both healthy and rTSA shoulders, the majority of the humeral-thoracic motion was provided by the glenohumeral motion. Therefore, the ratio of glenohumeral to scapulothoracic (ST) motion was always greater than 1.62 during elevation along the scapular plane. In comparison to healthy subjects, however, the contribution of ST motion to overall shoulder motion was significantly increased in the rTSA shoulders. This increased contribution was noted in all planes of shoulder elevation and was maintained when weights were attached to the arm. CONCLUSION: Kinematics of the rTSA shoulders are significantly altered, and more ST motion is used to achieve shoulder elevation.

Three-dimensional motion of the scapula and shoulder during activities of daily living.

The purpose of this study was to describe 3-dimensional scapular motion during the activities of daily living (ADL) and the full range of arm motion, and to suggest a standardized method for evaluating scapular mobility. Eight healthy subjects between the ages of 25-40, with no prior history of shoulder pathology or surgery for the past 12 months, were recruited for this study. Touching 8 predetermined landmarks on the head and the trunk was used to simulate ADL. Touching the contralateral ear and contralateral shoulder resulted in the maximum scapular protraction 46 degrees (8 degrees) and 48 degrees (8 degrees), respectively, and the maximum degrees of the scapular anterior tilt, -11 degrees (4 degrees) and -11 degrees (5 degrees), respectively. Asking patients to reach to the back of the neck, and the contralateral shoulder, the clinician can evaluate the overall scapular mobility in all directions. A protocol controlling the performance variability during ADL tasks was suggested to improve the clinical evaluation of the shoulder joint complex. Findings of this study can guide clinicians to identify specific tasks which may relate to particular shoulder girdle dysfunction.

Effects of aging on Type II muscle fibers: a systematic review of the literature.

The authors conducted a systematic review of the literature for scientific articles in selected databases to determine the effects of aging on Type II muscle fibers in human skeletal muscles. They found that aging of Type II muscle fibers is primarily associated with a loss of fibers and a decrease in fiber size. Morphological changes with increasing age particularly included Type II fiber grouping. There is conflicting evidence regarding the change of proportion of Type II fibers. Type II muscle fibers seem to play an important role in the aging process of human skeletal muscles. According to this literature review, loss of fibers, decrease in size, and fiber-type grouping represent major quantitative changes. Because the process of aging involves various complex phenomena such as fiber-type coexpression, however, it seems difficult to assign those changes solely to a specific fiber type.