• 한국운동역학회지
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• 제20권2호
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• pp.191-196
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• 2010

The purpose of this study was to investigate the effect of gait speed and walkway slope on the body acceleration, for the future validation of using an accelerometer in the estimation of energy consumption. Ten young healthy subjects with accelerometers on the upper thigh and ankle walked on a treadmill at 9 conditions(three speeds ${\times}$ three slopes) for 5 minutes. Acceleration signals of four directions, i.e. anterior-posterior(AP), medio-lateral(ML), superior-inferior(SI) and vector sum(VS) directions, of each sensor were measured, and root means squared(RMS) values of them were used as analysis variables. As statistical analysis, repeated measure two-way ANOVA was performed for RMS accelerations at each attachment sites, with slope and velocity as independent factors. At both the upper thigh and ankle, RMS acceleration of all directions were affected by gait velocities(p<.001) showing greater accelerations for higher velocities. Contrary to expectations, no slope effect existed in RMS accelerations at hip. Moreover, RMS acceleraion at ankle decreased with slope in SI and VS directions(p<.01). These results suggests that RMS acceleration cannot reflect the change in physical activity due to the change in walkway slope.

• 대한의용생체공학회:의공학회지
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• 제30권6호
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• pp.516-520
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• 2009

The purpose of this study is to determine optimal filtering condition and threshold for the detection of gait-cycles for various walkway slopes as well as gait velocities. Ten young healthy subjects with accelerometer system on thigh and ankle walked on a treadmill at 9 conditions (three speeds and three slopes) for 5 minutes. Two direction signals, i.e. anterior-posterior (AP) and superior-inferior (SI) directions, of each sensor (four sensor orientations) were used to detect specific events of gait cycle. Variation of the threshold (from -1G to 1G) and lowpass cutoff frequency (fc) were applied to the event detection and their performance was evaluated according to the error index (EI), which was defined as the combination of the accuracy and false positive rate. Optimal fc and threshold were determined for each slope in terms of the EI. The optimal fc, threshold and their corresponding EI depended much on the walkway slope so that their coefficients of variation (CV) ranged 19~120%. When all data for 3 slopes were used in the identification of optimal conditions for each sensor, the best error indices for all sensor orientations were comparable ranging 1.43~1.76%, but the optimal fc and threshold depended much on the sensor position. The result indicates that the gait-cycle detection robust to walkway slope is possible by threshold method with well-defined filtering condition and threshold.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.635-636
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• 2009

• 한국운동역학회지
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• 제26권2호
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• pp.161-166
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• 2016

Objective: The purpose of this study was to determine the knee and ankle joint kinematics and kinetics by comparing downhill walking with valley-shape combined slope walking. Method: Eighteen healthy men participated in this study. A three-dimensional motion capture system equipped with eight infrared cameras and a synchronized force plate, which was embedded in the sloped walkway, was used. Obtained kinematic and kinetic parameters were compared using paired two-tailed Student's t-tests at a significance level of 0.05. Results: The knee flexion angle after the mid-stance phase, the mean peak knee flexion angle in the early swing phase, and the ankle mean peak dorsiflexion angle were greater during downhill walking compared with valley-shape combined slope walking (p < 0.001). Both the mean peak vertical ground reaction force (GRF) in the early stance phase and late stance phase during downhill walking were smaller than those values during valley-shape combined slope walking. (p = 0.007 and p < 0.001, respectively). The mean peak anterior GRF, appearing right after toe-off during downhill walking, was also smaller than that of valley-shape combined slope walking (p = 0.002). The mean peak knee extension moment and ankle plantar flexion moment in late stance phase during downhill walking were significantly smaller than those of valley-shape combined slope walking (p = 0.002 and p = 0.015, respectively). Conclusion: These results suggest that gait strategy was modified during valley-shape combined slope walking when compared with continuous downhill walking in order to gain the propulsion for lifting the body up the incline for foot clearance.

• 한국전문물리치료학회지
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• 제8권1호
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• pp.89-96
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• 2001

This study addresses the effects of treadmill training on hyperextended knee and cadence in patients with hemiplegia. A single subject research design with multiple baselines across individuals was used for the study. Two patients with hemiplegia participated in the experiment. The experiment consisted of interventions where the patients were asked to ambulate for 15 minutes at a comfortable walking speed on the treadmill with 11% slope grade and were allowed to rest for 10 minutes. Patients, then, were asked to ambulated 20 meters at walkway. The number of occurrences of knee hyperextension and the total number of steps were recorded. The results showed that the occurrence of knee hyperextension decreased by approximately 30% after the first session of the treadmill training and continued to gradually decrease during the following sets of treadmill training. Meanwhile, there was a slight increase in the cadence to a negligible extent. These results suggest that the gait training on the sloped treadmill may be helpful for correcting the knee hyperextension in patients with hemiplegia.

• 한국전통조경학회지
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• 제32권4호
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• pp.132-142
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• 2014

본 연구는 영국 낭만주의 정원과 구별되는 미국 낭만주의 정원의 특성을 밝히기 위한 초기 연구로, 미국 초기 국가시대 영국의 낭만주의 정원이 처음 도입되기 시작하여 전환기 정원으로 언급되고 있는 파커정원, 마운트 버논과 몬티첼로 정원을 분석하였다. 분석은 문헌을 통해 시대적 배경, 정원을 조성한 인물, 정형식 정원과 자연주의 정원의 특성 등을 조사하였고, 문헌고찰과 현장답사를 통해 수집된 자료를 중심으로 각 대상지의 공간구조 원리와 정원요소를 중심으로 분석하였다. 공간구조 원리는 직선과 곡선, 노단과 구릉, 가시적 축과 비가시적 축, 대칭과 비대칭, 원근법과 사원근법을 분석인자로 하였다. 분석결과 각 정원은 초기국가 전시대인 식민지 시대 정원에서 보여지는 정형식 정원과 달리 자연주의 정원 즉, 비정형식 정원(영국 자연주의 정원) 양식이 공존하였다. 즉, 파카정원은 정형식 정원과 자연주의 정원이 각각의 공간에 계획되어 각각의 공간에 양식적 특성이 잘 나타나고 있었으나 정형식 정원에서 중심축의 계획에 있어서 거주지의 축과 정원의 축이 일치하지 않아 기존의 정형식 정원의 틀에서 벗어났음을 알 수 있었다. 이러한 현상과 한 정원 내에 자연주의적 정원이 공존 한다는 사실은 미국 초기 국가시대에 계획되어졌던 정형식 정원 양식이 다른 양식으로 대체된 것을 입증한다. 마운트 버논 정원은 파커정원에서와 같이 각각 다른 공간으로 나뉘어 계획된 것이 아니라 하나의 정원에 두 가지 양식이 서로 조화롭게 혼합되어 계획되어졌다. 구불구불한 산책로가 도입되었으나 중심축에 의한 좌우 대칭을 이루게 하였으며, 동일한 식재를 통해 대칭 등 정형적 계획이 동시에 고려된 것으로 나타났다. 반면 구릉의 테라스, 사원근법을 통한 공간계획 등을 통해 본격적으로 자연주의적 양식이 미국 정원에 정착하고 있음을 알 수 있었다. 몬티첼로의 분석결과 자연주의 정원의 대표적 특성인 구불구불한 산책로, 장식농장, 곡선의 화단과 사원근법 등의 원리로 공간이 계획되어 졌으며, 곡선의 화단, 숲과 덤불 형태의 식재 등 정형식 정원의 모습은 거의 찾아 볼 수 없는 영국에서 도입된 자연주의 정원의 특성이 완벽하게 재현된 것을 알 수 있었다.