• 대한지역사회영양학회지
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• 제21권6호
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• pp.520-532
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• 2016

Objectives: The objective of this study was to assess energy expenditure and metabolic cost (METs) of walking activities of college students and to compare treadmill based walking with self-selected hallway walking. Methods: Thirty subjects (mean age $23.4{\pm}1.6years$) completed eight walking activities. Five treadmill walking activities (TW2.4, TW3.2, TW4.0, TW4.8, TW5.6) were followed by three self-selected hallway walking activities, namely, walk as if you were walking and talking with a friend: HWL (leisurely), walk as if you were hurrying across the street at a cross-walk: HWB (brisk) and walk as fast as you can but do not run: HWF (fast) were performed by each subject. Energy expenditure was measured using a portable metabolic system and accelerometers. Results: Except for HWF (fast) activity, energy expenditures of all other walking activities measured were higher in male than in female subjects. The lowest energy expenditure and METs were observed in TW2.4 ($3.65{\pm}0.84kcal/min$ and $2.88{\pm}0.26METs$ in male), HWL (leisurely) ($2.85{\pm}0.70kcal/min$ and $3.20{\pm}0.57METs$ in female), and the highest rates were observed in HWF (fast) ($7.72{\pm}2.81kcal/min$, $5.84{\pm}1.84METs$ in male, $6.65{\pm}1.57kcal/min$, $7.13{\pm}0.68METs$ in female). Regarding the comparison of treadmill-based walking activities and self-selected walking, the energy expenditure of HWL (leisurely) was not significantly different from that of TW2.4. In case of male, no significant difference was observed between energy costs of HWB (brisk), HWF (fast) and TW5.6 activities, whereas in female, energy expenditures during HWB (brisk) and HWF (fast) were significantly different from that of TW5.6. Conclusions: In this study, we observed that energy expenditure from self-selected walking activities of college students was comparable with treadmill-based activities at specific speeds. Our results suggested that a practicing leisurely or brisk walking for a minimum of 150 minutes per week by both male and female college students enable them to meet recommendations from the Physical activity guide for Koreans.

• 한국운동역학회지
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• 제16권4호
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• pp.83-94
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• 2006

The purpose of this study is to elucidate how walking speed influences on change of angles of lower extremity and ground reaction force in normal and obese people. One group with normal body weight who were experimented at a standard speed of 1.5m/s and the other obese group were experimented at two different walking speeds (standard speed of 1.5m/s and self-selected speed of 1.3m/s). We calculated angles of lower extremity and ground reaction force during stance phase through video recording and platform force measuring. When the obese group walked at the standard speed, dorsi-flexion angle of ankle got bigger and plantar-flexion angle of ankle got smaller, which were not statistically significant. There was no significant difference of knee joint angles between normal and obese group at the same speed walking but significant post hoc only for the first flexion of knee joint in obese group. $F_z1$ was bigger than $F_z3$ in vertical axis for ground reaction force in both groups at the standard speed walking and the same force value at self-selected speed in obese group. $F_y3$ was always bigger than $F_y1$ in anterior-posterior axis in both groups.

• 한국정밀공학회지
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• 제27권2호
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• pp.123-129
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• 2010

The purpose of study is to investigate the correlation between the Lyapunov exponent (LE) and the displacement of the center of gravity (DCG) for clarifying walking stability on the treadmill. From fifteen young healthy subjects volunteered, lower extremity joint angles were recorded using a three-dimensional motion capture system with reflective markers. The anteroposterior DCG and the LE were calculated by a commercial software. A linear correlation between LE and DCG (p<0.05) showed that LEs compensated for walking distance on the treadmill walking. However, LEs were found to be independent of self-selected walking speeds by a negligible correlation between LE and the Froude number (p>0.05).

• 한국전문물리치료학회지
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• 제9권1호
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• pp.43-51
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• 2002

Physiological Cost Index (PCI) of walking has been widely used to predict oxygen consumption in healthy subjects or patients. The purpose of this study was to evaluate the predictability of physiological cost index of walking for the amount of exercise and cardiac function. Walking exercise was conducted in 67 healthy children (age 4-12) with a self-selected comfortable walking speed on the level surface. Walking speed was calculated, and heart rate was measured before and immediately after the walking. PCI was calculated for statistical analysis. The results were as follows; 1) The walking speed tends to increase and PCI of walking tends to decrease with age. There was significant difference in walking speed and PCI of walking among three age groups (p<.05). The change of walking heart rate tends to decrease with age, however, there was no significant difference among three age groups. 2) Linear regression equation between walking speed and age was 'Y (walking speed) = 2.124X (age) + 48.286' ($R^2$=.337), (p=.00). 3) The walking heart rate tends to decrease with age. Linear regression equation between walking heart rate and age was 'Y (walking heart rate) = 143.346 - 2.63X (age)' ($R^2$=.3425), (p=.00). 4) The walking heart rate decreased as body surface area (BSA) increased. Linear regression equation between walking heart rate and BSA was 'Y (walking heart rate) = 149.830 - 27.115X (BSA)' ($R^2$=.3066), (p=.00). In conclusion, these equations and PCI could be useful to quantify the variation of energy expenditure of children with pathological gait when compared with age-matched healthy children.

• 대한물리의학회지
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• 제14권1호
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• pp.7-14
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• 2019

PURPOSE: This study examined the effects of observing a self-video or a video of another person performing balance and gait training, followed by actual performance of the observed movements on the balance and walking ability of chronic stroke patients. METHODS: Thirty patients, who had experienced a stroke and were admitted to S rehabilitation hospital for treatment, were selected randomly and divided into three groups with 10 patients each: self-action observation (SAO) group, other-action observation (OAO) group, and treadmill walking training (TWT) group. The training program was conducted five times per week for four weeks. The GAITRite system, 10 m walking test, and timed up and go test were performed to measure the subjects' gait and balance ability. RESULTS: The velocity, cadence, double support, and stride length were increased significantly in the SAO and OAO groups (p<.05) but the T group showed no significant changes; no significant difference was observed among the groups (p >.05). The 10MWT decreased significantly in the OAO group (p<.05), but there were no significant changes in the SAO and T groups, and no significant difference was observed among the groups (p>.05). The TUG decreased significantly in the SAO and OAO groups (p<.05), but there were no significant changes in the T group, and no significant difference was observed among the groups (p>.05). CONCLUSION: The self or other action observation training helps improve the balance and gait ability.

• 한국콘텐츠학회논문지
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• 제13권10호
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• pp.444-451
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• 2013

본 연구의 목적은 노인과 정상 성인의 보행경로 너비에 따른 보행 시, 시 공간적 보행 변수의 변화를 알아보기 위함이다. 연구의 대상자는 낙상의 경험이 없는 건강한 노인 20명과 20대 성인 18명으로 하였으며, 3가지 다른 너비의 보행경로(평상시 보행(usual walking), 좁은 너비 보행(narrow base walking), 한줄 보행(centerline-guided walking)에서 보행을 실시하였다. 평상시 보행은 보행경로에 제한을 두지 않았고, 좁은 너비 보행은 각 대상자의 양측 ASIS 사이의 거리를 1/2로 나눈 너비를 보행경로로 설정하였으며, 한줄 보행은 보행경로 중앙에 한 줄을 표시하여 보행을 실시하였다. 보행을 실시하는 동안, GAITRite system을 이용하여 시 공간적 보행 변수의 변화를 비교 분석하였다. 보행경로 너비에 따른 시 공간적 보행 변수 비교에서 20대 성인은 모든 변수에서 유의한 차이를 나타내지 않았으나, 노인의 경우 보행속도, 분속수, 양 뒤꿈치 사이 기저면, 기능적 보행지수가 통계적으로 유의하게 감소하였다(p<.05). 본 연구의 결과를 통해 노인은 20대 성인에 비해 보행경로의 너비가 좁아질수록 낙상에 대한 두려움으로 인해 보행변수에 영향을 미친다는 것을 확인할 수 있었으며, 이를 통해 노인의 낙상 예방 훈련을 위한 적절한 보행너비에 대한 이론적 근거를 제시할 수 있을 것으로 생각된다.

• 대한영양사협회학술지
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• 제23권1호
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• pp.78-93
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• 2017

The purposes of this study were to assess energy expenditure of eight walking activities in normal weight and overweight or obese high school students and to evaluate the accuracy of two accelerometers worn on the ankle and waist. Thirty-five (male 17, female 18) healthy high school students participated in this study. They were classified into normal weight (n=21) and overweight or obese (n=14) groups. The subjects completed five treadmill walking activities (TW2.4, TW3.2, TW4.0, TW4.8, TW5.6), followed by three self-selected hallway walking activities (walk as if walking and talking with a friend: HWL, walk as if hurrying across the street at a cross-walk: HWB, walk as fast as you can but do not run: HWF). Energy expenditure and metabolic equivalents (METs) were measured using a portable indirect calorimeter, and predicted energy expenditures and METs were derived from two accelerometers placed on the ankle and waist. Measured energy expenditures per body weight (kg) of eight walking activities were significantly higher in the normal weight group than in the obese group and significantly higher in female than male. The ankle accelerometer overestimated energy expenditures and METs (bias 49.4~105.5%), whereas the waist accelerometer underestimated energy expenditures and METs (bias -30.3~-85.8). Except for HWF (fast) activity, METs of seven activities were moderate intensity based on Compendium METs intensity categories. HWF (fast) activity was vigorous intensity. METs from the ankle accelerometer were vigorous intensity except TW2.4 activity (moderate intensity). METs from the waist accelerometer were low intensity (TW2.4, TW3.2, TW4.0, TW4.8, HWL) and moderate intensity (TW5.6, HWB, HWF). Physical activity guidelines were developed based on measured physical activity level of high school students. Further studies should investigate the effects of body composition in larger subjects.

• 국제물리치료학회지
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• 제9권4호
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• pp.1576-1585
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• 2018

Regularly participating in physical activity is known to improve quality of life and body composition in elderly with stroke. However, comparatively less physical activity is performed by the stroke survivors. The factors related to inactivity in elderly female stroke survivors have not been elucidated. Therefore, this study aims to compare the quality of life factors and limb compositions between the active and inactive elderly female stroke survivors. Forty nine subjects between the ages of 65 to 75 years were selected from the KNHANES data between the years 2009 to 2011. In addition, 186 agematched healthy peers were also selected for limb composition comparisons. The subjects were groups based on walking days per week: walkers; 3 days or more, non-walkers; less than 3 days per week. BMI and waist circumference were within the obesity ranges for both the non-walkers and walkers. As results, the trend for greater fat (${\pm}10%$) and lean mass (${\pm}30%$) differences were observed for non-walker and walkers, respectively. Significantly greater reasons for function limitation by stroke and hypertension were reported with significantly greater self-care difficulty was shown by the walkers. In conclusion, elderly female stroke survivals may require customized motivation and continuous support to participate in physical activity regularly.

• 한국정밀공학회지
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• 제28권6호
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• pp.687-693
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• 2011

Spring-mass models have been widely accepted to explain the basic dynamics of human gait. Researchers found that the leg stiffness increased with gait speed to increase energy efficiency. However, the difference of leg stiffness change with gait speed between the young and the elderly has not been verified yet. In this study, we calculated the lower limb stiffness of the elderly using walking model with an axial spring. Vertical stiffness was defined as the ratio of the vertical force change to the vertical displacement change. Seven young and eight elderly subjects participated to the test. The subjects walked on a 12 meter long, 1 meter wide walkway at four different gait speeds, ranging from their self-selected speed to maximum speed randomly. Kinetic and kinematic data were collected using three force plates and motion capture cameras, respectively. The vertical stiffness of the two groups increased as a function of walking speed. Maximum walking speed of the elderly was slower than that of the young, yet the walking speed correlated well with the optimal stiffness that maximizes propulsion energy in both groups. The results may imply that human may use apparent limb stiffness to optimize energy based on spring-like leg mechanics.

• Physical Therapy Rehabilitation Science
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• 제6권3호
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• pp.134-139
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• 2017

Objective: Dual-task interference is defined as decrements in performance observed when people attempt to perform two tasks concurrently, such as a verbal task and walking. The purpose of this study was to investigate the changes of gait ability according to the dual task interference in chronic stroke survivors. Design: Cross-sectional study. Methods: Ten chronic stroke survivors (9 male, 1 female; mean age, 55.30 years; mini mental state examination, 19.60; onset duration, 56.90 months) recruited from the local community participated in this study. Gait ability (velocity, paretic side step, and stride time and length) under the single- and dual-task conditions at a self-selected comfortable walking speed was measured using the motion analysis system. In the dual task conditions, subjects performed three types of cognitive tasks (controlled oral word association test, auditory clock test, and counting backwards) while walking on the track. Results: For velocity, step and stride length, there was a significant decrease in the dual-task walking condition compared to the single walking condition (p<0.05). In particular, higher reduction of walking ability was observed when applying the counting backward task. Conclusions: Our results revealed that the addition of cognitive tasks while walking may lead to decrements of gait ability in stroke survivors. In particular, the difficulty level was the highest for the calculating task. We believe that these results provide basic information for improvements in gait ability and may be useful in gait training to prevent falls after a stroke incident.