• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.27 no.3
• /
• pp.89-98
• /
• 2021

Purpose: The purpose of this study was to determine the effects of electromyography (EMG)-biofeedback based closed kinetic chain exercise (CKCE) on quadriceps muscle activity and dynamic balance ability in patellofemoral pain syndrome (PFPS). Methods: Thirty subjects with PFPS were included and they were divided into EMG-biofeedback using CKCE (Group I) and squat exercise using CKCE (Group II), each group consisted of 15 patients. Group I and Group II was performed by the patients for three times a week, for six weeks. sEMG was used to measure quadriceps muscle activity and star excursion balance test (SEBT) was used to measure dynamic balance ability. Results: According to the results of the comparisons between the groups, after intervention, quadriceps muscle activity and dynamic balance ability were significantly higher in Group I than in the Group II. Conclusion: Findings of this study suggest that EMG-biofeedback using CKCE that provides real-time biofeedback information on muscle contraction may have a beneficial effect on selective muscle strength of vastus medialis oblique muscle and dynamic balance ability in PFPS.

• Journal of the Korean GEO-environmental Society
• /
• v.19 no.7
• /
• pp.5-11
• /
• 2018

Instead of a single pile, group piles are usually used for the pile foundation. If the earthquake occurs in the ground where group piles are installed, dynamic behavior of group piles are affected not only by interaction of piles and the ground movement but also by the pile cap. However, in Korea, the pile cap influence is not taken account into the design of group piles. Research on dynamic behavior of group piles has been performed only to verify interaction of piles and the ground and has not considered the pile cap as a factor. In this research, 1g shaking table model tests were performed to verify the thickness of the pile cap affects dynamic behavior of group piles that were installed in the ground where the earthquake would occur. The test results show that, as thickness of the pile cap increased, acceleration and horizontal displacement of the pile cap decreasd while vertical displacement of the pile cap increased. The results also showed that, among the group files tested, acceleration, horizontal displacement, and vertical displacement of the bearing pile are smaller than those of the friction pile.

• PNF and Movement
• /
• v.17 no.2
• /
• pp.245-252
• /
• 2019

Purpose: The purpose of this study was to determine the effects of action observation training on lower limb muscle activity and dynamic balance in chronic stroke patients. Methods: This study evaluated 20 chronic stroke patients who were divided randomly into a control and an experimental group comprising 10 patients each. Both the experimental group and the control group performed the general exercise therapy provided by the hospital, but the experimental group also performed action observation training. Lower limb muscle activity was measured with a surface electromyograph, and dynamic balance was measured with the Timed Up and Go test and the 10-meter walk test. The paired t-test was used to compare the groups before and after the experiment. Furthermore, the independent t-test was used to assess differences in the degree of change between the two groups before and after the experiment. Results: The within-group comparisons for both the experimental group and the control group showed significant differences in muscle activity and dynamic balance (p<0.05). In a comparison between the groups, the differences in the muscle activity and dynamic balance of the experimental group appeared significant compared with those of the control group (p<0.05). Conclusion: The study results indicate that action observation training is effective in improving the muscle activity and dynamic balance of chronic stroke patients.

• Physical Therapy Rehabilitation Science
• /
• v.2 no.1
• /
• pp.39-43
• /
• 2013

Objective: The objective of this study is to investigate the effect of treadmill gait trainig on dynamic balance and gait functions in stroke patients. Design: Randomized, double-blind, controlled pilot study. Methods: Four subjects following first stroke participated in this study. They were divided randomly into the treadmill gait trainig group (TM group) (n=2) and the control group (n=2). Subjects in both groups received general training five times per week. Subjects in the TM group practiced an additional treadmill gait trainig program that consisted of 60 minutes, three times per week, during a period of four weeks. Timed up and go test (dynamic balance) and the GAITRite test (gait function) were evaluated before and after the intervention. Results: In dynamic balance (timed up and go test), the TM group (-14.235 sec) showed a greater decrease than the control group (-13.585 sec). In gait functions, the TM group showed a greater increase in gait speed (12.8 cm/s vs. 10.15 cm/s), step-length (5.825 cm vs. 3.735 cm), and stride-length (5.005 cm vs. 1.55 cm) than the control group. Conclusions: The treadmill gait trainig improved dynamic balance and gait functions. Further research is needed in order to confirm the generalization of these findings and to identify which stroke patients might benefit from treadmill gait trainig.

• Physical Therapy Rehabilitation Science
• /
• v.10 no.4
• /
• pp.414-420
• /
• 2021

Objective: The purpose of this study was to investigate the effects of coordinative locomotor training(CLT) using elastic bands on dynamic balance and grip strength for Elementary school baseball players and to provide correct posture guidance and reference on the prevention and rehabilitation program of sports damage and injury in the future. Design: Two groups pre-post randomized controlled design. Methods: Forty-six subjects were randomly divided in two groups;1) CLT using Elastic Band group(Experimental group, n=23), 2) Routine baseball training group(Control group, n=23). The intervention was conducted total 16 times for sixty minutes a day, 2 times a week, for 8 weeks. Evaluations of dynamic balance ability and grip strength were performed with all subjects before the commencement of training and 8 weeks after training. Results: Compared to the control group after training, the dynamic balance ability and dominant handgrip strength of the experimental group were significantly more improved(p<0.05). Conclusions: We confirmed that the effects of CLT using elastic bands on dynamic balance ability and grip strength in Elementary school baseball player. This study should be used for improving the quality of the Elementary school baseball player's training and would be contributed prevention and rehabilitation program of sports damage and injury.

• The Journal of Korean Physical Therapy
• /
• v.35 no.5
• /
• pp.125-131
• /
• 2023

Purpose: This study examined the acute effects of static and dynamic stretching on the flexibility of the hamstring, dynamic balance ability, and function of the lower extremities in healthy adults. Methods: Thirty participants were assigned randomly to three groups: static stretching group (SSG), basic dynamic stretching group (BDSG), and 5 sec dynamic stretching group (5DSG). SSG performed three sets of 30 seconds of static stretching. BDSG performed a single-leg deadlift (SLD) at the same time as SSG, and 5DSG performed SLD held for five seconds. Hamstring flexibility, dynamic balance ability, and lower extremity function were evaluated before and after intervention. Results: The hamstring flexibility significantly improved in all groups (p<0.05). The dynamic balance ability improved significantly after intervention in all groups except BDSG in the anterior direction (p<0.05). There were significant differences in the posterolateral and posteromedial direction in all groups. The function of the lower extremity showed significant improvement over time only in BDSG (p<0.05). Conclusion: This study suggested that basic dynamic stretching and 5 sec dynamic stretching positively affect the hamstring flexibility, dynamic balance ability, and lower extremity function. Therefore, it is recommended to include dynamic stretching in a program for improving the hamstring flexibility, dynamic balance ability, and the lower extremity function. In addition, it is recommended to apply it at different times depending on the purpose.

• Structural Engineering and Mechanics
• /
• v.83 no.3
• /
• pp.377-386
• /
• 2022

This paper considers dynamic impedance functions and presents a detailed analysis of the soil plasticity influence on the pile-group foundation dynamic response. A three-dimensional finite element model is proposed, and a calculation method considering the time domain is detailed for the nonlinear dynamic impedance functions. The soil mass is modeled as continuum elastoplastic solid using the Mohr-Coulomb shear failure criterion. The piles are modeled as continuum solids and the slab as a structural plate-type element. Quiet boundaries are implemented to avoid wave reflection on the boundaries. The model and method of analysis are validated by comparison with those published on literature. Numerical results are presented in terms of horizontal and vertical nonlinear dynamic impedances as a function of the shear soil parameters (cohesion and internal friction angle), pile spacing ratio and frequencies of the dynamic signal.

• Journal of The Korean Society of Integrative Medicine
• /
• v.7 no.1
• /
• pp.1-8
• /
• 2019

Purpose : The purpose of this study was to examine the correlation between static and dynamic balance according to the virtual reality-based squat and conventional squat exercise. Methods : Twenty four participants were randomly assigned to the virtual reality-based squat (VRS) group (n=12) or conventional squat (CS) group (n=12). The static balance (C90 area, C90 angle, trace length, sway average velocity) and dynamic balance (forward, rearward, leftward, rightward) were measured using a force plate by BT4. The VRS group used the virtual reality system during 4 weeks, while the CS group underwent classical squat training. Independent t-test was used to test the homogeneity of the general characteristics of the subjects. The collected data was analyzed using the paired t-test for static and dynamic balance comparisons before and after exercise in both groups and Pearson's test for the correlation between static and dynamic balance according to the measured time. The significance level was set to 0.05. Results : There was no significant correlation between group and static and dynamic balance related variables (p>.05). There was a significant correlation between measurement time and static and dynamic balance related variables (p<.05). According to the measurement time, the static balance parameter C90 area in the VRS group after exercise was significantly decreased (p<.05). The values of forward, leftward and rightward in the VRS group were significantly increased after exercise (p<.05). Conclusion : It is suggested that 20 normal healthy adult men and women who have normal balance ability can improve their ability to control their posture by improving the balance ability when applying virtual reality-based squat exercise.

• The Journal of Korean Physical Therapy
• /
• v.34 no.3
• /
• pp.91-97
• /
• 2022

Purpose: This study investigated the short-term effectiveness of extracorporeal shock wave therapy (ESWT) on pain, the ankle instability, the ankle function, dorsiflexion range of motion (ROM), and dynamic balance in patients with chronic ankle instability (CAI). Methods: Eighteen participants were divided into an experimental (n=9) and control group (n=9). The ESWT in the experimental group was applied to the lateral collateral ligament in combination with the tibialis anterior whereas the ESWT was applied to the lateral collateral ligament of the ankle alone in the control group. Pain, the ankle instability, the ankle function, dorsiflexion ROM, and dynamic balance were measured using the Visual analog scale, Cumberland ankle instability tool, American Orthopedic Foot and Ankle Society ankle-hindfoot score, weight-bearing lunge, and Y-balance test, before and after ESWT intervention. Results: Significant interactions (group × time) and time effects were observed in the dorsiflexion ROM and dynamic balance. Bonferroni's post-hoc analysis showed that the experimental group revealed a more significant change in dorsiflexion ROM and dynamic balance than the control group. There was a significant time effect in the pain, the ankle instability, and the ankle function, but no significant interaction (group × time) was observed. Conclusion: The ESWT could improve the pain, ankle instability, ankle function, dorsiflexion ROM, and dynamic balance in patients with CAI. Furthermore, the ESWT combined with lateral ankle ligaments and tibialis anterior more improves the dorsiflexion ROM and dynamic balance.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.1134-1135
• /
• 2006

In this paper, dynamic simulation results for magnetically-levitated vehicles are resented. The dynamic equation and models for a half-bogie system are derived. The system includes primary suspension system, magnet module, spring-damper system and cabin. Also, the dynamic characteristics for the derived models are analysed. Using the results, levitation control algorithm can be designed to meet the performance requirements.