Background: Floor sit-to-stand (FSTS) places a higher load on the knees than chair sit-to-stand (CSTS). It is difficult to experimentally measure the maximum knee joint force during sit-to-stand motion. Objectives: This study's objectives were twofold: firstly, to quantify the differences in knee joint force between FSTS and CSTS, and secondly, to identify the angles at which the maximum knee joint force occurs during these motions. Design: Computer simulation study. Method: This study was conducted on 4 adult male subjects in their 20s. The FSTS and CSTS motion trajectories of the subjects were acquired using 3- dimensional motion analysis equipment. Using these, the human body mass model of the program was modified according to the subject, and the knee joint force was calculated. Also, the knee angle at which the maximum knee joint force occurs was found. Results: When the subjects performed the FSTS motion, a knee joint force that was up to about 160% higher than that of the CSTS motion occurred, and the angle at which the maximum knee joint force occurred was different between the sitting sequence(FSTS motion: 56~58 degree, CSTS motion: 78~82 degree) and the standing sequence(FSTS motion: 98~100 degree, CSTS motion: 70~74 degree). Conclusion: By comparing FSTS motion with CSTS motion, it is expected that it can be used as a quantitative guide for the effect of motion similar to FSTS motion on the knee when prescribing exercise for the elderly or patients with knee-related lesions.
Background: Proprioception in the ankle joint is important for maintaining balance. There is a correlation between joint position sense (JPS), balance and ankle dorsiflexion range of motion (DF-ROM). Objectives: The purpose of this study was to compare the effects of talocrural joint mobilization (TJM) and muscle energy technique (MET) of plantar flexor muscle (PF) on improving joint position sense (JPS) and static balance. Design: Cross-over randomized trial research. Methods: Sixteen participants (male 10, female 6; 20’s of their age) without ankle instability were recruited. In a randomized, three conditions, no intervention, talocalcaneal mobilization, and PF-MET were all applied to 16 participants. For TJM, the Kaltenborn grade 3 joint gliding method, in which the talus moves posteriorly perpendicular to the tacrocrural joint plane, were used. In the PF-MET, MET method were applied gastrocnemius muscle and soleus muscle with 25% of 1 Repeat Maximum of each muscle. The all participants performed PF-MET and TJM for 18 minutes. DF-ROM measured the weightbearing lunge test. JPS measured using the active joint angle reproduction test. Static balance was measured displacement of center of pressure parameter. Results: PF-MET and TJM had significant differences in DF-ROM and AP displacements. PF-MET significantly increased at 5° and 15° of plantar flexion and 5° of dorsiflexion, and COP velocity significantly decreased in JPS compared to TJM. Conclusion: PF-MET and TJM are effective in increasing DF-ROM. However, PF-MET has a more positive effect on improving JPS and static balance than on talocrural joint mobilization.
본 연구의 목적은 허벅다리걸기 시 유도 선수들의 무릎 관절 부상 경험이 운동학적 요인과 압력 중심 요인들에 미치는 영향을 분석하는데 있었다. 본 연구에는 허벅다리걸기를 특기로 하는 오른손잡이 남 자 대학 유도 선수 중 최근 2년 이내 무릎 관절 부상 경험이 있었던 13명(연령, 20.69.1±0.75 세; 신장, 172.85±4.81 cm; 체중, 74.92±5.51 kg; 경력, 8.92±0.95 세)과 상해 경험이 없었던 13명(연령, 21.08.1±0.76 세; 신장, 172.54±6.32 cm; 체중, 76.62±9.09 kg; 경력, 9.46±0.94 세)이 두 그룹으로 나 뉘어 피험자로 참여하였다. 두 그룹의 발목, 무릎, 힙 관절각도 변인과 압력 중심 가동범위와 속도 요인들 의 차이를 분석하였다. 그 결과, 부상 경험 그룹은 부상 경험이 없었던 그룹에 비해 허벅다리걸기 기술 발 휘 시 한발 지지 구간 중 E3에서의 무릎 관절 굴곡 각도와 E4에서의 힙 관절 신전 각도에서 작은 수치를 나타내었다. 더불어 부상 경험 그룹은 부상 경험이 없었던 그룹에 비해 한발 지지 구간에서 압력 중심 가동 범위와 전방 이동 속도 요인에서도 낮은 수치를 나타내었다.
A universal joint is a device that transmits the power of a combat vehicle engine to a cooling fan. The power of the engine is transmitted to the universal joint as it is without buffering, and play occurs at the joint between the drive shaft connected to the engine and the driven shaft connected to the cooling fan according to the usage time. Accordingly, the universal joint is periodically replaced, and the criterion for this is the degree of torsion of the universal joint. However, if the universal joint is not properly maintained during the replacement cycle, damage to the universal joint as well as damage to the surrounding power supply may occur. Accordingly, a backlash measuring device was developed to determine the limit of durability of the universal joint, and the limit of durability was derived through regression analysis of the backlash value according to the use time obtained from the accelerated life test.
Synovial cysts of the temporomandibular joint are rare. They commonly occur in the wrist, knee and feet. The main symptoms of synovial cysts occurring in the temporomandibular joint include preauricular pain and swelling, and surgical removal is the gold-standard treatment. A 54-year-old woman who presented with swelling of the right temporomandibular joint visited Kyungpook National University Dental Hospital. She had undergone enhanced computed tomography from another hospital, which showed a 1.1 × 0.8 × 1 cm well-defined rounded cystic lesion on the lateral area of the right temporomandibular joint. A synovial or ganglion cyst was suspected. The cystic lesion was surgically removed under general anesthesia and was histopathologically diagnosed as a synovial cyst. Histopathological findings show a lumen surrounded by loose fibrous tissue, and the lining is in a folded form and is composed of synovial cells.
Previous research on green product innovation (GPI) has primarily focused on the performance of new product development, neglecting the critical, early fuzzy front-end (FFE) phase. Drawing upon the firm's resource-based view (RBV) and dynamic capabilities perspective, this study explores how co-production affects FFE outcomes (creative idea and product definition proficiency) of GPI and whether joint learning ambidexterity is a mediating mechanism in international buyer-supplier relationships. Additionally, we provide a contingency perspective by considering the moderating role of the innovation ecosystem on the relationship between co-production and joint learning ambidexterity. Finally, this study contributes to a theoretical understanding, analyzing co-production as a predictor, joint learning ambidexterity as a mediator, and innovation ecosystem as a moderator.
Background: As sedentary life increases, people's thoracic vertebra joint movement decreases, and the resulting associated pain is complaining of a lot of discomfort. This is also affecting the autonomic nervous system. Objectives: The purpose of this study was therefore to find out the effect of thoracic vertebra joint mobilization on heart rate variability in upper back pain patients. Design: Randomized controlled trial. Method: Thirty subjects in this study were randomly assigned to two groups of 15 persons each using a randomization tool. Maitland's grade III joint mobilization, hot pack, and interferential current therapy (ICT) were applied to T1-L2 and hot pack and ICT were applied to the control group. The intervention was performed 3 times a week for 4 weeks. Results: There were statistically significant changes in Visual Analog Scale (VAS), Standard Deviation of all Normal R-R Intervals (SDNN), Low Frequency (LF), High Frequency (HF) and LF/HF ratio in the study group, and statistically significant changes in VAS, SDNN, and LF/HF ratio in the control group. In comparison of differences, there were statistically significant changes in VAS. Conclusion: Positive effects were found on SDNN and LF/HF ratio in both the joint mobilization group and the control group compared to before the study. In particular, even LF and HF were positive in the joint mobilization group showed influence.
Background: The Trunk Stabilization Exercise and Respiratory Muscle Exercise may help address the complex biomechanical and neuromuscular issues that contribute to shoulder joint disorders and can help improve patient outcomes in terms of pain relief, range of motion, and functional ability. Objectives: To investigated the effects of conventional physical therapy, trunk stabilization exercise, and respiratory muscle exercise, on the Range of Motion (ROM), ULF and balance in patients with shoulder joint disorder. Design: A randomized controlled trial. Methods: This study randomly allocated 18 subjects to the control group, 19 to the trunk stabilization exercise group, and 19 to the respiratory muscle exercise group, while all interventions were performed five times a week for four weeks. The result measurement involved the ROM, the upper limb function test (ULT), and balance tests. Results: The respiratory muscles exercise group indicated significant improvement in ROM and balance tests than the trunk stabilization exercise group and control group. Conclusion: The respiratory muscle exercise is a more effective way to improve ROM and balance ability than trunk stabilization exercise for patients with shoulder joint disorder.
This study aims to empirically investigate effects of motion repetition and external load according to joint motion on discomfort through an experiment. Eighteen college students (female: 9; male: 9) participated in an experiment measuring perceived discomfort using the Borg CR10. Joint(wrist, elbow, shoulder and trunk) motion, its repetition and external load were adopted as independent variables. The results showed that all three independent variables were statistically significant on discomfort. Participants’ sex also significantly affected discomfort obtained in the experiment. While the interactions of joint motion and repetition, and joint motion and external load were not significant at α = 0.05, that of motion repetition and external load was significant. Based on the experimental results, four regression equations by the joints involved were presented, which could be used as a tool for evaluating postural loads by the joints. It may be postulated that based on the results of this study, scoring systems of RULA and REBA, and those of OWAS and REBA underestimates effects of motion repetition and external load, respectively. It is expected that the results of this study will be used as a basic data for developing an observational method properly reflecting the effects of motion repetition and external load.
Background: The gluteus maximus (GM) muscle comprise the lumbo-pelvic complex and is an important stabilizing muscle during leg extension. In patients with low back pain (LBP) with weakness of the GM, spine leads to compensatory muscle activities such as instantaneous increase of the erector spinae (ES) muscle activity. Four-point kneeling arm and leg lift (FKALL) is most common types of lumbopelvic and GM muscles strengthening exercise. We assumed that altered hip position during FKALL may increase thoraco-lumbar stabilizer like GM activity more effectively method.
Objects: The purpose of this study was investigated that effects of the three exercise postures on the right-sided GM, internal oblique (IO), external oblique (EO), and multifidus (MF) muscle activities and pelvic kinematic during FKALL.
Methods: Twenty eight healthy individuals participated in this study. The exercises were performed three conditions of FKALL (pure FKALL, FKALL with 120° hip flexion of the supporting leg, FKALL with 30° hip abduction of the lifted leg). Participants performed FKALL exercises three times each condition, and motion sensor used to measure pelvic tilt and rotation angle.
Results: This study demonstrated that no significant change in pelvic angle during hip movement in the FKALL (p > 0.05). However, the MF and GM muscle activities in FKALL with hip flexion and hip abduction is greater than pure FKALL position (p < 0.001).
Conclusion: Our finding suggests that change the posture of the hip joint to facilitate GM muscle activation during trunk stabilization exercises such as the FKALL.
본 연구에서는 가설 강교에 사용되는 조립식 거더-교각 접합부에 대한 새로운 설계를 제안하였다. 새로운 접합부는 모듈의 각 부분을 공장에서 용접하여 제작한 후 현장에서 용접 대신 볼트 접합부를 사용하도록 구성하여 현장에서 모듈을 신속 하게 조립하도록 구성하였다. 이 새롭게 제안된 거더-교각 접합부의 구조적 성능을 평가하기 위해 정적 거동, 연성 성능 및 회 전 성능을 분석하는 실험을 수행하였다, 실험결과 제안된 볼트 접합부는 기존의 용접 체결부에 비해 정적 지지력, 연성 거동 및 회전 성능에서 우수한 성능을 보여주었다. 비록 볼트 체결부의 강성이 용접 체결부보다 다소 작지만, 체결부의 연성 성능이나 정적 지지력에 큰 영향을 미치지 않았으며, 안전성 향상, 빠른 조립 및 분해, 건설 공기 단축 등의 유리한 특성으로 인해 가설 교량 건설에 적합한 것으로 평가되었다.
Background: Despite its high prevalence, interventions in plantar fasciitis remain inconclusive. To improve the daily life of plantar fasciitis patients, it is necessary to identify appropriate interventions to improve pain and foot pressure and balance. Improving the interventions for plantar fasciitis is one of the main goals for rehabilitation.
Objectives: To investigate the changes in pain and static-dynamic foot pressure and balance through the evaluation of 42 plantar fasciitis patient before and after the foot stretching and joint mobilization interventions.
Design: Randomized controlled trial.
Methods: The 42 subjects of the study were divided into a stretching group and a joint mobilization group with 21 subjects being assigned to each group. The results before and after the experiment were analyzed by applying stretching and joint movement interventions for a total of 6 weeks.
Results: Before and after the intervention, there were significant improvements in the pain index and static-dynamic foot pressure and static balance in both stretching and joint mobilization groups. However, the between-group comparison indicated no significant differences.
Conclusion: The stretching and the joint mobilization can improve the pain and static-dynamic foot pressure and static balance in plantar fasciitis patients.
Due to its excellent processability, thermal conductivity and high corrosion resistance, copper tubes applied to heat exchangers are being joined through brazing to increase heat exchange efficiency. In order to improve performance, the issue of joint quality of copper tubes, a major member of heat exchangers, is emerging, so research is needed to obtain excellent joint quality of brazing joints that may be damaged. In this study, the quality change of joints according to process variables was studied through induction heating brazing experiments using high frequency. The depth of penetration, which indicates the quality of the junction, was measured, and the center position of the high-frequency electrode and the height of the electrode, which change the location of the heat source applied to the junction, were selected as process variables. Lastly, the thermal image data obtained between the brazing experiments were obtained and the joint quality according to the temperature gradient of the joint was analyzed.