Background : There is lack of studies on the effects of the bag-carrying style on the shoulder muscles and body alignment in adults with rounded shoulder posture (RSP). Objective: The purpose of this study was to investigate the effects of various bag-carrying styles on muscle tone, muscle stiffness and spinal alignment in 20 adults with RSP as they were walking on a treadmill. Design : Crossover Study Design. Methods: A subject performed treadmill walking for 15 minutes at a speed of 4 ㎞/ｈ while carrying three different types of bags: a backpack, a cross bag, and a shoulder bag. Results : The results showed that the main effect of timing was observed in the muscle tone for all the variables and in muscle stiffness only for the upper and lower trapezius muscles. As for the main effect of timing, the muscle tone of the upper trapezius and the pectoralis major significantly increased in all conditions, while the muscle tone of the lower trapezius significantly decreased in all conditions. The muscle stiffness of the upper trapezius significantly increased in all conditions, while the muscle stiffness of the lower trapezius significantly decreased in all conditions. As for the spinal alignment, the dimple distance data values significantly decreased for the cross-bag style. Conclusions : This study demonstrated that walking with a heavy bag, regardless of the bag-carrying style, increased muscle stiffness around the shoulders in adults with rounded shoulder posture, and walking with a crossbag also induced changes in spinal alignment.

Background: Although previous researches have developed interventions for neck problems, headache, and temporomandibular disorder in patients with forward head posture (FHP), changes in masticatory muscle tone or stiffness as FHP worsening have not been investigated. Objective: To examine changes in masticatory muscle tone and stiffness through craniovertebral angle (CVA). Design: Cross sectional study Methods: The subjects were 21 healthy males with normal head posture. Three CVA were established for posture measurement in which the bilateral anterior temporal and masseter muscles were measured during the subjects maintained a series of postures. Results: The Right masseter muscle significantly increased in stiffness with advancing FHP (p < 0.05). No significant changes were observed in the muscle tone or stiffness of any other masticatory muscles, and no significant differences were found in bilateral masticatory muscle tone or stiffness in each measurement posture. Conclusions: This study suggests that the increased stiffness of the right masseter muscle as the FHP worsened requires consideration in physical therapy assessment and intervention.

The structural performance of a vehicle can be evaluated by the static and dynamic structural analyses which predict the amounts of deformation & stiffness, and the static analysis should be done first. Another important aspect to be considered in the design process is crashworthiness, because a structurally sturdy vehicle body may be overdesigned with the excessive strength and durability standards. The ideal condition of a body structure is to absorb the impact load at a certain level of local deformation, to distribute the load to each structure adequately, and to prevent the excessive stress concentration and deformation. This paper is the result of the consideration of vibration characteristic for structure stiffness estimation of automotive body through the finite element modeling.

The structural performance of a vehicle can be evaluated by the static and dynamic structural analyses which predict the amount of deformation, stiffness. And the static analysis should be done first. Another important aspect to be considered in the design process is crashworthiness, because a structurally sturdy vehicle body may be overdesigned with excessive strength and durability standards. The ideal condition of a body structure is to absorb impact load at a certain level of local deformation, to distribute the load to each structure adequately, and to prevent excessive stress concentration and deformation. This paper is the result of the consideration of automotive body, bending and torsional stiffness for structure stiffness estimation of automotive body through finite element modeling.

Background: Previous researchers have investigated the mechanical and neurophysiological effects of manual mobilization, however little research has been done on muscle tone and muscle stiffness. Objective: To compare the effects of posterior-anterior (PA) mobilization with weight bearing on sling and conventional PA mobilization on the bed. Design: Randomized controlled trial (single blind) Methods: The subjects were 16 male university students and randomized to sling mobilization group (SMG, n=8) or conventional mobilization group (CMG, n=8). SMG received PA mobilization using a sling and CMG received traditional mobilization on the bed during lumbar mobilization. Results: Both left and right muscle tones of SMG increased, but left muscle tone of SMG were increased and right muscle tone was decreased after intervention. In addition, both left and right muscle stiffness of SMG were also increased, however left muscle stiffness of SMG was increased and right muscle stiffness was decreased. The muscle tone and muscle stiffness of SMG were higher than those of DMG, especially the right side was statistically significantly higher. Extension of SMG, extension and flexion of CMG were increased statistically significantly except for Flexion of SMG (p<.05). There were no significant differences between the groups in Extension and Flexion. Conclusions: This study suggests that lumbar spine PA mobilization using sling is beneficial in improving muscle tone, muscle stiffness, and trunk movement.

Background : Although plank exercises is reported to the changes in muscle activity of the deep muscles and superficial muscles among the core muscles. However, no study has examined the effects of forearm plank exercise on tone and stiffness in the superficial back line muscle. Objective: To compare the effects of sling forearm plank exercises and mat forearm plank exercises on the superficial back line muscle tone and stiffness. Design: Randomized controlled clinical trial (single blind) Methods: The subjects were randomized to sling forearm plank exercise group (N = 8) or mat forearm plank exercise group (N = 8). The measurements were taken for each research group following exercises: the muscle tone and stiffness of upper lumbar muscles, lower lumbar muscles, long head of biceps femoris, and medial part of gastrocnemius among the superficial back line muscles. Results: Sling forearm plank exercise group Indicated statistically significant increases in stiffness of medial part of gastrocnemius (p<.05). However, mat forearm plank exercise group reported no statistically significant in muscle tone and stiffness of all measured muscles. No significant differences in measured variables were found between the groups. Conclusions: These results suggest that the forearm plank exercise performed with an unstable surface in the defined sling can increase the stiffness of calf muscle, but it is unlikely to achieve increases in muscle tone and stiffness of the overall superficial back line muscles.

본 연구는 만 70~85세의 고령여성을 대상으로 주 1회 아쿠아로빅과 주 2회 맨손근력운동을 실시하는 복합운동프로그램을 12주간 적용하여 혈중 염증인자, DHEA-s 및 동맥경직도에 미치는 영향을 구명하기 위하여 운동군 21명, 대조군 21명으로 구분하여 실시하였다. 1회 운동지속시간은 60분으로 4주 간격으로 운동강도를 점진적으로 증가시켜 실시하였다. 복합운동 전과 후에 측정된 자료의 상호작용 효과 검증을 위해 이원반복측정 분산분석을 실시하였고, T검정을 사용하여 사후분석을 하였으며, 유의수준은 .05로 설정하여 분석하였다. 그 결과 12주간의 복합운동은 고령여성의 염증반응을 감소 시켰으며, DHEA-s가 증가함에 따라 노화호르몬에도 긍정적인 영향을 미치는 것으로 나타났다. 동맥경직도는 중심동맥혈압(수축기, 이완기)이 감소하였고, 맥압 및 파형증가지수의 증가를 완화하였으며, 맥파전파속도를 감소시키는 것으로 나타났다. 이상의 결과 고령여성의 건강한 노화와 장수를 위해서 항염증, 노화호르몬의 개선 및 혈관건강의 역할로 규칙적이고 지속적인 복합운동이 권장 될 수 있을 것으로 사료된다.

Recently, the concept of an outrigger damper system with a damper added to the existing outrigger system has been developed and applied for dynamic response control of high-rise buildings. However, the study on the structural characteristics and design method of Outrigger damper system is in the early stages. In this study, a 50 story high - rise building was designed and an outrigger damper system with viscoelastic damper was applied for wind response control. The time history analysis was performed by using the kaimal spectrum to create an artificial wind load for a total of 1,000 seconds at 0.1 second intervals. Analysis of the top horizontal maximum displacement response and acceleration response shows that outrigger damper systems are up to 28.33% and 49.26% more effective than conventional outrigger systems, respectively. Also, it is confirmed that the increase of damping ratio of dampers is effective for dynamic response control. However, since increasing the damping capacity increases the economic burden, it is necessary to select the appropriate stiffness and damping value of the outrigger damper system.

본 연구에서는 탄소나노튜브/화이버/폴리머 복합소재 구조에 대한 재료 물성 및 강성 추정을 다룬다. 수정된 Halpin-Tsai 모델을 적용한 멀티 스케일 해석은 탄소나노튜브의 함유량 비율, CNT 두께-길이 비율, 화이버 부피 함유량, 그리고 화이버 보강각도 변화에 따라서 수행되었다. 본 연구에서 제시한 멀티-스케일 접근방법은 기존 모델을 적용하여 얻은 결과와 비교하여 검증하였다. 매개변수 해석을 통하여 CNT의 적절한 함유량은 적층된 CNTFPC 구조의 구조성능의 향상시킬 수 있는 중요한 특성을 규명하였다.

본 연구는 테이핑 적용방법에 따른 근긴장도, 근경직도 및 악력의 변화를 알아보기 위해 실시하였다. 연구의 대상자는 20대 정상 성인 30명을 대상으로 하여 테이프를 늘리지 않고 붙이는 방법(non stretched taping)과 테이프를 늘려 붙이는 방법(stretched taping)을 통해 변인들을 측정하였다. 근긴장도와 근경직도는 Myoton pro 장비를 이용하여 측정하였으며, 악력계를 이용하여 악력을 측정하였다. 않은 자세에서 측정하였으며, 테이핑을 적용하기 전과 적용한 후를 대상자별로 임의로 순서를 정하여 측정하였고, 같은 동작에서 3번 측정하여 평균값을 사용하였다. 테이핑 적용에 따른 근긴장도, 근경직도 및 악력의 비교를 위하여 대응검정을 이용하여 분석하였으며, 중재 전·후에서 그룹간 차이를 보기 위하여 독립검정을 실시하였다. 본 연구의 결과 non stretched taping 적용과 stretched taping 적용 모두에서 근긴장도, 근경직도는 두 그룹 모두에서 통계적으로 유의한 감소를 보였으며, 악력은 두 그룹 모두에서 통계적으로 유의한 증가를 나타내었다. 그룹간 차이는 중재 전 근긴장도, 근경직도 및 악력은 차이가 나타나지 않았다. 중재 후 그룹간 차이는 근긴장도, 근경직도는 통계적으로 유의한 차이를 나타내지 않았으나, 악력의 경우 통계적으로 두 그룹간 유의한 차이가 나타났으며, stretched taping 그룹에서 더 높은 값을 나타내었다. 테이핑 적용 방법에 따른 근긴장도와 근경직도, 악력의 차이가 있기 때문에 테이핑 방법을 잘 적용하여 사용한다면 근육의 효과를 기대할 수 있을 것이다.

The hydro-forming design process of the sub-frame side members was studied using a high strength steel of 440 MPa in tensile strength. In the part design stage of the side member, the cross section analysis and the overall process design of the part shape were done. In the detailed simulation results, the maximum thickness reduction rate due to hydro-forming was predicted to be 13% and this was predicted to be a safe level without cracking. The end curvature was reduced to increase the stiffness of the part to design more secure parts and two types of grooves were added to the cross section and compared. The thickness reduction rates of the narrow and wide were improved by 18.6% and 15.6%, respectively when the narrow and wide grooves were added.

This study aimed to investigate the influence of walking on crural muscle tone and stiffness in individuals with bilateral pronated foot. This study consisted of 16 healthy male. Subjects were divided into a pronated foot group (n = 8) and a normal foot group (n = 8). The navicular drop test on both foot and muscle tone and stiffness in tibialis anterior muscle, medial gastrocnemius muscle, and peroneus longus muscle of both lower extremities were measured before and after 30 min of walking. In this study, the measured navicular drop test before walking was significantly different between pronated foot group and a normal group(p < .05). After 30 min of walking, significantly, increased medial gastrocnemius muscle stiffness of the non-dominant leg was found in the pronated foot group (p < .05). However, there was no significant difference in medial gastrocnemius muscle stiffness between the two groups (p > .05). Based on this study, pronated foot needs to be managed to prevent the abnormally increased medial gastrocnemius muscle stiffness.

The purpose of the study was to investigate the immediate effects of negative pressure soft tissue therapy on muscle tone, muscle stiffness and balance in patients with stroke. In total, 20 patients with stroke and assigned to the negative pressure soft tissue therapy group (NPST, n=10) or, placebo-negative pressure soft tissue therapy group(Placebo-NPST, n=10). Both groups underwent NPST or placebo-NPST once a day during the experimental period. MyotonPRO was used to assess the parameters for muscle tone and stiffness. Biorescue was used to assess the parameters for balance. Each group showed improvements in muscle tone, muscle stiffness, and balance ability (p<.05). Especially, Muscle tone, muscle stiffness, and anterior length in the limit of stability were the significant improvement on NPST group (p<.05). The results of the study suggest that the NPST is effective in improving muscle tone, muscle stiffness, and balance ability in patients with stroke.

Background: After a stroke, the patient may have abnormal muscle tone due to abnormal alignment. Physical therapists have used stretching, neural mobilization other methods to treat patients after stroke. In addition, joint mobilization is also used to stimulation in pathway of cervical segmental region and to normal cervical spine alignment. Objects: The purpose of this study was to determine whether Maitland cervical spine mobilization has an immediate effect on muscle tone and stiffness of upper extremity. Methods: Thirty subjects were divided into a experimental group (n1=10), a placebo group (n2=10), and a control group (n3=10). The Maitland cervical spine mobilization was applied in the supine position. Immediately after the intervention, muscle tone and stiffness of biceps brachii, brachioradialis, deltoid, and pectoralis major were measured using Myoton®PRO. In the placebo group, sham mobilization was applied to the fifth and sixth cervical vertebra, and the control group was instructed to control breathing. Results: In the experimental group, significant differences were found in muscle tone and stiffness of biceps brachii and brachioradialis in comparison with the affected side and the non-affected side before the intervention (p<.05), whereas there was no significant difference after the intervention (p>.05). Muscle tone of biceps brachii on the non-affected side and pectoralis major on the affected side was significantly decreased before and after the intervention (p<.05). The placebo and control group showed no changes on the non-affected and affected side, and no significant differences were detected before and after the intervention. All the groups revealed no significant differences in muscle tone and stiffness of upper extremity before and after the intervention. Conclusion: This study suggests that the application of Maitland cervical spine mobilization enhanced muscle tone of upper extremity on the involved side symmetrically, and influenced a decrease in muscle tone

Recently, road cave-in and depression in urban area due to subsurface cavity are emerging as a social issue in Korea. These phenomena enable to cause not only damage to human lives and properties, but also an anxiety of the citizens. Furthermore, it is a problem that needs more fundamental solution to countermeasure. The objective of this study is to evaluate the stiffness characteristics of asphalt pavement with existence of subsurface cavity using Falling Weight Deflectometer (FWD) deflection and backcalculation analysis using GAPAVE program developed the KICT. The characteristics of FWD deflections are analysed for cavity and intact asphalt pavements. The stiffness reduction in the asphalt pavement due to subsurface cavity was evaluated as a result of this FWD test. The Seoul Metropolitan Government has conducted a Ground Penetrating Radar (GPR) test, coring, and image photographing in four different locations to determine the presence of the cavity and figure out the cavity depth and size underneath asphalt pavements. The cavity depths measured in this section range between 17cm to 51cm, and its lengths are at least 70cm to up to 310cm. It is found from this analysis that the deflections measured from cavity section are generally higher than intact section in same locations. As results of backcalculation analysis, it appears that the backcalculated moduli are generally decreasing with increase of cavity depth. After comparing with AC moduli obtained from intact and cavity section, it is observed that about 80% of moduli was reduced with existence of subsurface.

Following the earthquake that shook the city of Gyeongju, Korea, in 2016, it became apparent that research on the safety of cultural heritages against the seismic hazards is necessary in Korea. Predictions of how historically significant stone pagodas would behave the earthquakes anticipated in near future, which are the subject of this study, is also required. In this study, the dynamic characteristics of 15 cultural heritage designated stone pagodas of Korea were investigated, including natural frequency and damping ratio, and the stiffness of the stone material and its contact area were determined using eigenvalue analysis by assuming the stone pagodas to be multi-degree-of-freedom structures. The results of this study enable the structural modeling of stone pagodas using a finite element analysis program and the method is expected to be useful in assessing the structural safety of stone pagodas against vertical loads as well as lateral forces, including earthquakes. Also, by identifying the dynamic characteristics of the structures, the results of this study can be utilized as a nondestructive testing method to determine the rigidity of cultural heritage structures and to identify inherent problems. The natural frequencies of the Korean stone pagodas were measured to be within 3.5~8.3㎐, excluding cases with distinct natural frequency results, and it was determined that the natural frequencies of the stone pagodas are influenced by various parameters including the height and joint stiffness of the structures.

The purpose of this study is to determine the stiffness of rubber of dynamic damper. This damper system reduces the steering wheel vibration caused by idling oscillation of the engine. Therefore, in order to measure the stiffness of the silicone rubber in the dynamic damper system, the material test of the silicone rubber was carried out. Using the measured stiffness, the FEM model of the dynamic damper system was constructed and the correlation by the experimental data was shown at an error of less than 2%. In addition, the dynamic damper system was simplified to a two-degree-of-freedom spring-mass model and the effect of the stiffness change of the rubber on the natural frequency of the column shaft was analyzed theoretically. As a result, the amplitude of the column shaft was reduced as the stiffness of the silicone rubber was lowered.

본 연구는 대사증후군을 가진 65세 이상 노인여성을 대상으로 마루운동을 실시하여 노인활동체력, 혈중지질 및 동맥경직도에 미치는 영향을 조사하였다. 대사증후군을 가진 여성노인 41명을 무작위로 운동군(23명), 통제군(18명)으로 배정하였다. 운동군은 총 12주간 주 3회로 실시하였으며, 운동강도는 30%-60%의 HRR로 점진적으로 증가시켰다. 본 연구결과, 운동군이 노인활동체력(하지근력, 상지근력, 유연성, 심폐지구력 및 신체조성(체지방률, 제지방량, 허리둘레)), 혈중지질(총 콜레스테롤, 중성지방, HDL 콜레스테롤 및 LDL 콜레스테롤) 및 동맥경 직도에서 실험 전·후 긍정적인 변화를 보였고, 통제군에 비해 유의한 차이를 나타냈다. 결과적으로 대사증후군을 가진 여성노인들은 마루운동 프로그램 참여에 따라 노인활동체력이 향상되고, 혈중지질과 동맥경직도에 긍정적인 변화가 일어났다. 따라서, 마루운동프로그램은 대사증후군 개선에 효과적인 프로그램임을 시사한다.