• Physical Therapy Korea
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• v.19 no.3
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• pp.51-60
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• 2012

This study aimed to determine the usefulness of classifying patients with neck pain on the basis of the results of passive scapular elevation test. We classified 21 patients with neck pain into positive (n=12) and negative (n=9) groups on the basis of passive scapular elevation test; the 2 groups then equally performed scapular stabilization exercise program for 30 min, 3 times a week, for 4 weeks. Visual analogue scale (VAS), neck disability index (NDI), and range of motion (ROM) were recorded both before and after the intervention for both groups. Paired t-test was used to determine that there were significant changes between before and after the intervention, and independent t-test was used for analyzing changes between two groups of dependent variables. After 4 weeks of training, we observed significant decrease in pain and disability (p<.05) and a significant increase in rotation, flexion, extension, and side-bending ROM (p<.05) in both groups. Further, between pre- and post-intervention evaluations, we observed a significant decrease in pain and disability and a significant increase in rotation and flexion ROM in the positive group than in the negative group (p<.05). These results indicate that passive scapular elevation test may be used to identify mechanical disorders of the cervicoscapular muscle in patients with neck pain. Therefore, we recommend the use of passive scapular elevation test to determine appropriate treatment intervention when treating patients with neck pain.

• Journal of Preventive Medicine and Public Health
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• v.29 no.3 s.54
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• pp.565-577
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• 1996

This study was conducted to evaluate the association of work posture with cervical spine abnormality toward 106 microwave-oven assemblers. A self-administered questionnaire was used to obtain a general characteristics and a work history of workers. The posture of neck and shoulder joint of workers were measured with video tape recording and the simple X-ray of cervical spine was checked-up to observe the X-ray abnormality including degenerative change, curvature abnormality, disc space narrowing or disc canal narrowing. The result were as follows. 1. The prevalence of degenerative change among cervicobrachial disorder workers was 44.3% (47 persons), curvature abnormality was 43.4%(46 persons), disc space narrowing was 21.7%(23 persons), and disc canal narrowing was 21.7%(23 persons). 2. The prevalence of degenerative change at cervical spine was increased with the degree of neck flexion(flexed versus neutral, odds ratio [OR]=2.7), the total work posture of neck(mild or severe awkward versus neutral ; OR=1.2, 3.4). 3. The prevalence of degenerative change at cervical spine was increased with the degree of the right shoulder flexion, the heaviness of the materials carried by the right hand and the degree of awkwardness at the total work posture of right shoulder(p<0.05). 4. There was no evidence of association between curvature abnormality, disc space narrowing, disc canal narrowing and work posture. In conclusion the awkward work posture was related with degenerative change of cervical spine among microwave oven assembling workers and the further study in these field must be made to prove the association objectively.

• Journal of Korean Neurosurgical Society
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• v.59 no.5
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• pp.425-429
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• 2016

Objective : Rod-screw fixation systems are widely used for spinal instrumentation. Although many biomechanical studies on rod-screw systems have been carried out, but the effects of rod contouring on the construct strength is still not very well defined in the literature. This work examines the mechanical impact of straight, $20^{\circ}$ kyphotic, and $20^{\circ}$ lordotic rod contouring on rod-screw fixation systems, by forming a corpectomy model. Methods : The corpectomy groups were prepared using ultra-high molecular weight polyethylene samples. Non-destructive loads were applied during flexion/extension and torsion testing. Spine-loading conditions were simulated by load subjections of 100 N with a velocity of $5mm\;min^{-1}$, to ensure 8.4-Nm moment. For torsional loading, the corpectomy models were subjected to rotational displacement of $0.5^{\circ}\;s^{-1}$ to an end point of $5.0^{\circ}$, in a torsion testing machine. Results : Under both flexion and extension loading conditions the stiffness values for the lordotic rod-screw system were the highest. Under torsional loading conditions, the lordotic rod-screw system exhibited the highest torsional rigidity. Conclusion : We concluded that the lordotic rod-screw system was the most rigid among the systems tested and the risk of rod and screw failure is much higher in the kyphotic rod-screw systems. Further biomechanical studies should be attempted to compare between different rod kyphotic angles to minimize the kyphotic rod failure rate and to offer a more stable and rigid rod-screw construct models for surgical application in the kyphotic vertebrae.

• Journal of Biomedical Engineering Research
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• v.26 no.3
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• pp.151-155
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• 2005

Interspinous spacers have been developed as an alternative surgical treatment for laminectomy or fusion with pedicle screws and rods for the treatment of lumbar spinal stenosis. However, its biomedical efficacies are well not known. In this study, we evaluated kinematic behaviors of the surgical and the adjacent levels before and after inserting interspinous spacers. Three porcine lumbar spines were prepared. On each specimen, an interspinous spacer was inserted at the L4-L5. Flexion-extension moments (0, 2.5, 5.0, 7.5, 10Nm) were applied. A stereophotogrammetric set-up with DLT algorithm was used to assess the three-dimensional motions of the specimen where three markers $({\square}0.8mm)$ were attached to each vertebra. Results showed that extension motion decreased by $15-24\%$ at the surgical level (L4-L5) after insertion of interspinous spacer. At the adjacent levels, the range of motion remained unchanged. In flexion, no significant changes in motion were observed regardless of levels. Therefore, our experimental results demonstrated the interspinous spacer is very effective in limiting the extension motion that may cause narrowing of the spinal canal and vertebral foramen while maintaining kinematic behaviors at the adjacent levels. Further, these results suggested that the use of interspinous spacer may be able to prevent lower back pain at the surgical level and to lower the incidence of degenerative changes at the adjacent levels.

• Physical Therapy Korea
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• v.15 no.1
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• pp.61-68
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• 2008

The aim of the study was to evaluate the effect of a disease-specific exercise (DSE) on temporomandibular joint (TMJ) function and neck mobility in TMJ dysfunction associated with ankylosing spondylitis (AS). Ten AS patients (seven males and three females) with TMJ dysfunction were recruited for this study. The DSE included exercises to correct head and neck posture and to improve the flexibility of the neck and TMJs. The patients attended treatment three times a week for 4 weeks, averaging 1 hour each session. Assessments were performed pretreatment, posttreatment, and 6 weeks after the completion of treatment. General physical status was assessed by four clinical measures (tragus-to-wall distance, modified Schober test, lumbar side flexion, and intermalleolar distance), the Bath ankylosing spondylitis function index (BASFI), and the Bath ankylosing spondylitis disease activity index. The main outcome measures included TMJ function (craniomandibular index (CMI)), and neck mobility (flexion, extension, rotation, and lateral rotation). None of the measures of general physical status, with the exception of BASFI, were significant1y different between the pretreatment, posttreatment, and 6-week follow-up (p>.05). However, CMI and all neck movements, except for extension, significant1y improved after the treatment (p<.05). These improvements were maintained during the follow-up period. The DSE used in the present study seems to be a clinical1y useful method for managing patients with symptoms from the stomatognathic system in AS. Further studies with more subjects and longer treatment times, including the follow-up period, will be conducted to validate these findings.

• The Korean Journal of Applied Statistics
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• v.26 no.6
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• pp.873-887
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• 2013

The axis of rotation in biomechanics is a major tool to investigate joint function; therefore, many methods to estimate the axis of rotation have been developed. However, there exist several problems to describe, estimate, and test the axis statistically. The axis is directional data(axial data) and it should not be analyzed with traditional statistics. A proper comparative method should be considered to compare axis estimating methods for the same given data ANOVA (analysis of variance) is a frequently used statistical method to compare treatment means in experimental designs. In case of the axial data response assumed to come from Watson distribution, there are a few ANOVA method options. This study constructed ANOVA models for within-subjects designs of axial data. Two models (one within-subjects factor and two within-subjects factors crossed design) were considered. The empirical data used in this study were instantaneous axes of rotation of flexion/extension at the knee joint and the flexion/extension and pronation/supination at the elbow joint. The results of this study can be further applied to the various analysis of experimental designs.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.16-23
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• 2018

Postural instability can increase the likelihood of hazardous slip and fall accidents in workplaces. The present study intended to extend understanding of the effect of abnormal neck posture on postural control during quiet standing. The effect of body fatigue on the postural control was also of primary concern. Twelve healthy undergraduate students volunteered to participate in the experiment. Standing on a force platform with the neck neutral, flexed, extended, or rotated, subjects' center of pressures (COP) were measured under the two levels of body fatigue. For the fatigue condition, Subjects exercised in a treadmill to meet the predetermined level of body fatigue. Analyzing the position coordinates of COPs, the length of postural sway path was assessed in both medio-lateral (ML) axis and anterior-posterior (AP) axis. Results showed that, in AP direction, neck extension or rotation significantly increased the sway length as compared with neck neutral. Neck extension led to greater sway length compared to neck rotation. Neck flexion did not differ from neck neutral. The sway length in the AP direction also became significantly larger as the body fatigue accumulated after treadmill exercise. In ML direction, as compared to neutral posture, the neck extension, flexion, or rotation did not significantly affect the length of postural sway path. However, the sway length seemed to increase marginally with the neck extended during the fatigued condition. This study demonstrates that abnormal neck posture may interfere with postural control during standing. The ability to maintain postural stability decreases significantly with the neck extended or rotated. Body fatigue leads to postural instability further.

• Physical Therapy Rehabilitation Science
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• v.6 no.1
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• pp.7-13
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• 2017

Objective: The aim of this study was to investigate the inter-rater and intra-rater reliability of rehabilitative ultrasound imaging (RUSI) for measurement of muscle thickness with changes in angles of the gluteus maximus (GM) at rest and during contraction. Design: Cross-sectional study. Methods: Twenty-two healthy men volunteered for this study. GM muscle images were obtained in the resting position and during prone hip extension with knee flexion at hip abduction angles of $0^{\circ}$ and $30^{\circ}$, respectively. Two examiners randomly measured the thickness of the GM twice in three different positions. The first position was a comfortable prone position. The second position was prone hip extension with knee flexion (PHEKF) to $90^{\circ}$. The third position was achieved by hanging a 1-kg weight on the ankle of the lifted leg during PHEKF with the angle of the lifted leg the same as the second position. Intra-class correlation coefficients (ICCs), standard error measurements, and minimal detectable changes were used to estimate reliability. Results: The intra-rater reliability ICCs (95% confidence interval) of the GM were >0.870, indicating good reliability. Inter-rater reliability ICCs ranged from 0.668 to 0.913. The reliability of measurements of muscle thickness at each position was similar to the reliability of the angle change. Differences in muscle thickness and ratios for each position with $0^{\circ}$ and $30^{\circ}$ of hip abduction were not statistically significant. Conclusions: In the present study, the intra-rater reliability of muscle thickness measurements of the GM was good, and the inter-rater reliability was moderate to good. Reliable RUSI measurements of wide and large muscles, such as the GM muscle at rest and during contraction, are feasible. Further investigation is required to establish the reproducibility of the protocols presented in this study.

• Physical Therapy Korea
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• v.13 no.1
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• pp.38-46
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• 2006

The purposes of this study were to investigate the median frequency (MDF) between initiation and termination of muscle contraction through surface electromyographic (sEMG) analysis and to propose the basis of clinical treatment for movement problems in early hemiparetic upper limbs. Thirteen patients who had stroke with onset less than 3 months prior to the study and seven control subjects participated in the study. The median frequency in initiation and termination of muscle contraction was recorded from wrist flexor and extensor muscles using the sEMG, with 3 second beeper signals, during maximal isometric wrist flexion and extension. Flexion and extension must be done as quickly and forcefully as possible. The results of the study were as follows: 1. The MDF of the onset and offset sections were significantly lower on the paretic than the nonparetic and control sides. 2. The MDF of the offset section significantly decreased on the paretic and nonparetic sides. Consequently, this study showed that the lowering of the MDF was due to the hemiparetic wrist motor impairment and muscle weakness. These results are also related to Fugl-Meyer motor assessment (FMA) scores in hemiparetic upper limbs. This study also suggests that since muscle weakness of early stroke patients affects the functional decrease of upper limbs, further studies must focus on the treatment to improve muscle agility and muscle fiber recruitment efficiency that can induce the functional recovery correlated to motor control.

• Clinics in Shoulder and Elbow
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• v.21 no.1
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• pp.15-21
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• 2018

Background: This study was undertaken to compare the outcome of supervised and home exercises with respect to range of motion (ROM), pain, and Single Assessment Numeric Evaluation (SANE). We further correlated the ROM recovery and pain reduction as well. Methods: The study included 49 patients who underwent arthroscopic rotator cuff repair. Rehabilitation was initiated after 4 weeks of immobilization. A total of 29 patients performed supervised exercise 3 times a week. Standardized education and brochures for review were provided to the remaining 20 patients who insisted on home rehabilitation. Statistical analysis was performed for comparing pain Numerical Rating Scale (NRS), SANE, and ROM. In addition, we also evaluated the correlation between pain and ROM. Results: Comparison of the two groups revealed no significant differences in forward flexion, internal rotation, abduction, and pain NRS. However, SANE at the 9th week (63.8 vs. 55.0, p=0.038) and improvement of external rotation from the 5th to the 9th week (17.6 vs. 9.3, p=0.018) were significantly higher in the supervised exercise group as compared to the home exercise group. Correlation of pain NRS with forward flexion, external rotation, internal rotation and abduction were statistically not significant (correlation coefficient=0.032 [p=0.828], -0.255 [p=0.077], 0.068 [p=0.642], and -0.188 [p=0.196], respectively). Conclusions: The supervised rehabilitation after arthroscopic rotator cuff repair showed better improvement in external rotation and higher SANE score after 4 weeks of rehabilitation exercise. However, no statistically significant correlation was observed between the recovery of ROM and short-term pain relief.