• PNF and Movement
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• 제17권2호
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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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• 제8권4호
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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.

• 대한정형도수물리치료학회지
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• 제17권2호
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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.

• 한국운동역학회지
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• 제24권4호
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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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• 제10권2호
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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.

• 한국산업정보학회논문지
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• 제5권1호
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• pp.77-86
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• 2000

최근 들어 산업현장에서는 생산성의 향상, 노무비의 증가 및 노동력의 부족, 안전성 등을 이유로 자동생산시스템과 운반용 동력기계와 같은 기구를 도입하여 작업자 스스로가 자신의 근력을 이용한 인력운반(Manual Materials Handling : MMH) 작업이 줄어들고 있는 추세라고 하지만, 실제로 비탈진 경사면에 위치한 농장이나 과수원, 항만부두의 하역작업, 경사진 벌목장 작업, 광산의 막장에서의 작업등과 같이 주변환경이 복잡한 현장에서의 작업은 기계로 완전히 대체하기가 어려운 실정이다. 그러므로, 이러한 작업현장에서는 인간이 직접 손 운반작업(들기 작업)을 할 수밖에 없으며, 이와 같은 경사면에서의 손 운반작업(들기 작업)은 작업자에게 많은 재해의 위험성을 만들어 주며, 추락으로 인한 산업재해는 물론이고 미끄러짐 방지 같은 신체균형잡기 노력은 근골격 계통에 과도한 무리를 주게 되어 LBP의 원인이 되기도 한다. 하지만, 이러한 경사면에서의 손 운반작업(들기 작업)에 대한 연구에 대해서는 거의 없는 실정이다. 따라서, 본 연구에서는 force platform을 이용하여 경사면에서의 손 운반작업(들기 작업)을 통한 COP변화를 측정 ·분석하여 작업자들의 산업재해를 예방하고자 하며, 향후 이러한 기초 자료를 통하여 손 운반작업(들기 작업)뿐만 아니라 그 밖의 응용분야에 기여하고자 한다.

• Physical Therapy Rehabilitation Science
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• 제6권4호
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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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• 제7권2호
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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.

• 산업경영시스템학회지
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• 제39권3호
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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.

• 한국운동역학회지
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• 제18권3호
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• pp.23-31
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• 2008

이 연구는 압력중심점 변수를 이용하여 고령 여성 그룹 20명($68.9{\pm}6.8$세)을 대상으로 눈뜨고 정적서기 테스트시 주로 사용되고 있는 두 발을 모아 나란히 붙인 위치(FTP)와 피험자 자신이 편하게 느끼는 간격으로 나란히 놓은 위치(PFP)에 따른 적절한 샘플링 시간을 알아보는데 목적이 있다. 샘플링 시간은 FTP 발 위치를 이용할 경우 20초 이상, PFP 발 위치를 이용할 경우 60초 이상이 적절한 것으로 나타났다. FTP 발 위치 20초와 PFP 발 위치 60초 보다 짧은 샘플링 시간은 안정성을 나타내는 샘플을 제공하지 않거나, 역으로 너무 길어지면 피로 유발로 인해 안정성을 나타내는 샘플을 왜곡시킬 수 있을 것이다. 차후 다양한 그룹들을 대상으로 적절한 샘플링 시간에 대한 추가 연구와 보다 긴 샘플링 시간으로 인해 나타나는 피험자들의 특이적인 현상에 대한 연구가 기대된다.