• Physical Therapy Korea
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• v.21 no.2
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• pp.8-17
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• 2014

The purpose of this study was to examine the effects of hip joint mobilization (HJM) on walking ability, balance ability, and the joint range of motion in stroke patients to minimize the problems of the musculoskeletal system in patients with central nervous system diseases. All volunteers were randomly assigned to the HJM group ($n_1=14$) and the general neurodevelopment therapy (NDT) group ($n_2=16$). The HJM procedure involved applying Maitland mobilization techniques (distraction, lateral gliding, inferior gliding, and anterior gliding) by grade 3 to both hip joint. The mobilization process included mobilization and NDT for 15 min/day, 3 days a week for 4 weeks. The outcome measures were evaluated, including the hip joint passive range of motion (ROM) test and femur head anterior glide test (FHAG) using prone figure four test, dynamic and static balance abilities [timed up and go (TUG) test and center of pressure (COP) analysis], and walking ability [10-meter walking test (10MWT) and 6-min walking test (6MWT)]. Both the groups showed significant post-training differences in the hip joint ROM (FHAG and degree of hip extension) and 10MWT. The post-training improvements in the TUG test were significantly greater in patients of the HJM group than in the NDT group; however, there were no post-training improvements in COP in both groups. Patients in the HJM group showed post-training improvement in the 6MWT; however, statistically significant differences were not observed. Patients in the NDT group showed post-training improvements in the 6MWT. These results suggest that HJM improves hip joint ROM, dynamic balance ability, and walking speed in stroke patients. However, further studies are required to evaluate the long-term therapeutic efficacy of HJM in stroke patients.

• PNF and Movement
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• v.17 no.2
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• pp.275-282
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• 2019

Purpose: This study aimed to investigate the optimal positions of safety grab bars for effective sit-to-stand (STS) movement by comparing the results of the STS movement while using a safety grab bar installed under two different conditions: the height of the grab bar installation was determined by (1) the Building Act and (2) the principle of proprioceptive neuromuscular facilitation (PNF). Methods: A total of 50 undergraduate students participated in this study, and they were required to perform an STS movement twice under each condition. A baropodometric platform for sitting and a Biorescue (RM Ingenierie, France) were used to collect and analyze changes in the center of pressure (COP) on the left and right sides before and after performing the STS movement. The average completion time for the STS movement was also measured for analysis. Moreover, the participants were asked to express their individual subjective preferences regarding the two positions of the grab bars. Results: The COP changes were significantly smaller when performing the STS movement with the grab bar installed at the height determined by the PNF principle than the Building Act (p<0.01), and the difference in the completion time of the STS movement was not statistically significant between the two conditions. Conclusion: The findings of this study suggest that the principle of PNF can be useful for planning therapeutic exercise as well as for proposing the optimal grab bar position for older adults and those with health-related issues when performing the STS movement. In addition, this may serve as a basic rehabilitation technique for maintaining remaining functions and providing functional efficiency.

• Physical Therapy Rehabilitation Science
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• v.8 no.4
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• pp.225-233
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• 2019

Objective: The purpose of this study was to examine the possible effects of incorporating short-term slow-abdominal respiration (SAR) into an exercise program, on balance and the cardiac-related autonomic nervous system (ANS). Design: Cross-over repeated measures design. Methods: Fifteen young and healthy adults were randomly assigned into two groups (7 in the C-R group, 8 in the R-C group), each of which carried out both control sequence (C) and respiration-experiment sequence (R) in the inverse order. In the C sequence, the subjects performed passive exercises and a general exercise program (P-GEP). In the R sequence, the subjects received a short-term SAR training session and then performed the respiration incorporated general exercises program (R-RGEP). Before and after both C and R sequences, the length and the area of the displacement of the center of pressure (COP) and heart rate variability parameters were measured. Results: The total length of the COP displacement in the left single-leg-standing condition showed a significantly greater reduction after R-RGEP in the respiration-experiment sequence than after the P-GEP in the control sequence (p<0.05). The mean heart rate was significantly reduced only after R-RGEP in the respiration-experiment sequence (p<0.05) Conclusions: The slow-abdominal-respiration, trained in a simple manner and integrated into the exercise program in a single session, showed partially positive immediate effects on balance stabilization. The decrease in heart rate indicated possible involvement of the parasympathetic ANS activation in the stability, although it is not enough to decide whether it is purely due to the controlled respiration.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.17 no.2
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• pp.25-32
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• 2011

Background: This study was to examine the effect of applying leg exercise using visual informations on improving stroke patient's muscle power, balance and gait. Methods: The subjects of this study were hemiplegic patients by stroke, 30 patients were picked up, who were agreed with this research and were having hospital care for 8 weeks at RS, RB and HH medical centers. The study group was 15 and comparison group was 15, totally 30 patients were confirmed. leg exercise using visual informations was applied to study group, leg exercise without visual informations was applied to comparison group. These were proceeded for 8 weeks (5 days a week, 20 minutes a day), change of muscle power, balance and gait was checked to investigate the effect. Electromyography apparatus was used for checking muscle power, K-BBS (Korean version of Berg Balance Scale) and COP (center of pressure) were used for balance, then Functional Gait Assessment (FGA), timed up and go test (TUG) were used for checking the capacity of gait. Results: Vastus lateralis (p=.002), biceps femoris (p=.000), K-BBS (p=.000), COP (p=.007), FGA (p=.002), TUG (p=.009) are significant difference between the two groups. Conclusion: This study showed that visual informations impact change of muscle activity, balance and locomotor ability in stroke patients.

• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.391-397
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• 2014

The purpose of this work is to biomechanically study the effect of the one leg standing pose in yoga.. The work have been done through the evaluation for the left and right symmetry ability of one leg standing pose in the before and after yoga training for the 14 female yoga subject group (height: $164.3{\pm}4.4cm$, mass: $53.4{\pm}6.4kg$, year: $20.0{\pm}0.49yrs$) participated in this experiment. The motions of one leg standing pose were captured with Vicon system and the parameters were calculated with Visual-3D and Ground reaction force system. The results were as followed; - Front and backward COPsd did not show the significant difference, compared the before training with the after. - Left and right COPsd showed the significant difference (p<0.05), compared the before training with the after. - COP distance showed the significant difference (p<0.01), compared the before training with the after. - The asymmetry index of front and backward COPsd did not show the significant difference, compared the before training with the after. - The asymmetry index of left and right COPsd did not show the significant difference, compared the before training with the after. - The asymmetry index of COP distance showed the significant difference (p<0.01), compared the before training with the after. Therefore, the yoga training demonstrated the stable improvement in the one leg standing pose of inferior feet and the positive effect to the left and right symmetry ability.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.161-166
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• 2021

Objective: The purpose of this study was to quantitatively evaluate the Wii Balance Board (WBB)-based jump performance for the elderly and to confirm the difference in jump performance according to age. Design: Cross-sectional study. Methods: 40 young adults (aged 22.5±2.2 years) and 33 elderly (aged 75.1±5.2 years) without orthopedics disease participated in this study. Standing on the WBB then, with the signal "start," jump vertically to the maximum height at which you can jump, land on the force plate after jump and keep it standing on both feet. All subjects were required to practice the jump sufficiently before starting the measurement, each measuring three times, and the mean values were used. A one-minute break was provided between each trial. Evaluators waited within 1meter for every test to prepare for fall. Results: The vertical ground reaction force of elderly and young adults when jumping using WBB showed a significant difference (p<0.05) and demonstrated discriminant validity. Between two groups, there were significant differences in overall jump time (p<0.05), maximum value (p<0.05), minimum value (p<0.05), center of pressure (COP) pathlength (p<0.05), and flight time p<0.05). Conclusions: This study found that performing the vertical jump, the elderly showed longer jump time, lower vertical ground reaction force, COP pathlength and shorter flight phase than healthy young adults using WBB and demonstrated that as a measurement tool, WBB discriminated vertical jump performance between elderly and young adults.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.77-86
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• 2000

Even manual materials handling tasks(MMHT) is decreasing by adopt of automatic manufacturing system & transportation supporting machine because of increase of productivity, wage lack of labor, safety, in fact working at inclined & complicated slope such as farm, orchard, harbor loading & unloading, logging place and mining place can't be substituted by machine perfectly. So, workers should do MMHT at this place by themselves, lifting on slope can cause much of hazard, include falling. Keeping balance net to slip can be a reason of low back pain(LBP) by overloaded musculoskeletal system but, there's no enough study about lift on slope. Therefore, In this study, we assessed and analyzed change of center of pressure(COP) when lifting on slope by force platform. The result showed that the length lengthen as increasing angle of slope. Especially, the length extremely increased over 15°. Through These basic result, present proper angle boundary, prevent industrial accidents and give proper data not only lifting but also pushing and pulling on slope someday.

• Physical Therapy Rehabilitation Science
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• v.6 no.4
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• pp.189-195
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• 2017

Objective: The purpose of this study was to examine the effects of real-time visual feedback weight shift training during golf swinging on golf performance. Design: Repeated-measures crossover design. Methods: Twenty-sixth amateur golfers were enrolled and randomly divided into two groups: The golf swing training with real-time feedback on weight shift (experimental group) swing training on the Wii balance board (WBB) by viewing the center of pressure (COP) trajectory on the WBB. All participants were assigned to the experimental group and the control group. The general golf swing training group (control group) performed on the ground. The golf performance was measured using a high-speed 3-dimensional camera sensor which analyses the shot distance, ball velocity, vertical launch angle, horizontal launch angle, back spin velocity and side spin velocity. The COP trajectory was assessed during 10 practice sessions and the mean was used. The golf performance measurement was repeated three times and its mean value was used. The assessment and training were performed at 24-hour intervals. Results: After training sessions, the change in shot distance, ball velocity, and horizontal launch angle pre- and post-training were significantly different when using the driver and iron clubs in the experimental group (p<0.05). The interaction time${\times}$group and time${\times}$club were not significant for all variables. Conclusions: In this study, real-time feedback training using real-time feedback on weight shifting improves golf shot distance and accuracy, which will be effective in increasing golf performance. In addition, it can be used as an index for golf player ability.

• Safety and Health at Work
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• v.7 no.2
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• pp.124-129
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• 2016

Background: Work-related fatigue has a strong impact on performance and safety but so far, no agreed upon method exists to detect and quantify it. It has been suggested that work-related fatigue cannot be quantified with just one test alone, possibly because fatigue is not a uniform construct. The purpose of this study is therefore to measure work-related fatigue with multiple tests and then to determine the underlying factorial structure. Methods: Twenty-eight employees (mean: 36.11; standard deviation 13.17) participated in five common fatigue tests, namely, posturography, heart rate variability, distributed attention, simple reaction time, and subjective fatigue before and after work. To evaluate changes from morning to afternoon, t tests were conducted. For further data analysis, the differences between afternoon and morning scores for each outcome measure and participant (${\Delta}$ scores) were submitted to factor analysis with varimax rotation and each factor with the highest-loading outcome measure was selected. The ${\Delta}$ scores from tests with single and multiple outcome measures were submitted for a further factor analysis with varimax rotation. Results: The statistical analysis of the multiple tests determine a factorial structure with three factors: The first factor is best represented by center of pressure (COP) path length, COP confidence area, and simple reaction time. The second factor is associated with root mean square of successive difference and useful field of view (UFOV). The third factor is represented by the single ${\Delta}$ score of subjective fatigue. Conclusion: Work-related fatigue is a multidimensional phenomenon that should be assessed by multiple tests. Based on data structure and practicability, we recommend carrying out further studies to assess work-related fatigue with manual reaction time and UFOV Subtest 2.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.39-46
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• 2016

Loss of postural stability can possibly lead to slip and fall accidents in the number of workplaces and everyday life. This study was aimed to examine the effects of whole body fatigue and partially limited visual field on the ability of maintaining postural balance during quiet standing. A group of twelve healthy male subjects participated in the experiment. Before and after experiencing the whole body fatigue induced by bicycling exercises, the position coordinates of subject's center of pressure (COP) were obtained under the two levels of visual field condition (i.e., open visual field and limited visual field). Four levels of the whole body fatigue examined were rest, 300watt, 600watt, and 900watt. Position coordinates of COPs measured on a force plate were then converted into the total length of postural sway path in both the medio-lateral (ML) direction and the anterior-posterior (AP) direction. Two-way ANOVA result showed that the length of sway path in the AP direction became significantly larger as the whole body fatigue accumulated. Post-hoc test revealed statistically significant differences between rest and 900watt and between 300watt and 900watt. The significant increase of the sway length was also found when the visual field was partially obstructed by the boxes. In the ML direction, however, there was no statistically significant difference of the postural sway in both the AP and ML directions. The results imply that the ability of maintaining postural stability can be reduced significantly due to such tasks along with whole body fatigue. The postural balance can also be impaired by the limited visual field.