• The Journal of Korean Physical Therapy
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• 제26권2호
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• pp.74-81
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• 2014

Purpose: The purpose of this study is to compare kinematics and kinetics on the knee joint between stair gait with unstable shoes and barefoot in healthy adult women. Methods: Seventeen healthy adult women were recruited for this study. The subjects performed stair ascent and descent with unstable shoes and barefoot. The experiment was repeated three times for each stair gait with unstable shoes and barefoot. Measurement and analysis of the movements of the knee joint were performed using a three-dimensional analysis system. Results: Statistically significant differences in the knee muscle force of semimembranosus, biceps femoris-long head, biceps femoris-short head and sartorius, patellar ligament, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair ascent. Statistically significant differences in the knee muscle force of sartorius, rectus femoris, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair descent. Statistically significant differences in the knee flexor moment of semitendinosus, biceps femoris-long head, biceps femoris-short head, sartorius, rectus femoris, vastus intermedialis, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair ascent. Conclusion: Therefore, wearing unstable shoes during stair gait in daily life is considered to influence knee joint kinematics and kinetics due to the unstable shoes, and thus suggest the possibility that reducing the risks of pain, and knee osteoarthritis, stabilizing the knee joint caused by changes in the loading of the knee joint.

• The Journal of Korean Physical Therapy
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• 제27권4호
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• pp.228-233
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• 2015

Purpose: Gait is the most basic element when evaluating the quality of life with activities of daily living under ordinary life circumstances. Symmetrical use of the lower extremities requires complicated coordination of all limbs. Thus, this study examined asymmetry of muscle activity quadriceps femoris and tibialis anterior as a baseline for training during over-ground walking and stair walking of stroke patients. Methods: Subjects were 14 stroke patients included as one experimental group. Gait speed used in this study was determined by the subject. Low extremity paretic and non-paretic EMG was compared using the surface EMG system. Results: The low extremity EMG difference was statistically significant during over-ground walking and stair walking (p<0.05). The result of low extremity EMG substituted symmetry ratio formula was compared to EMG symmetry ratio in both legs during over-ground walking and stair walking. The average symmetry ratio of quadriceps femoris during over-ground walking was 0.65, and average symmetry ratio of quadriceps femoris during stair walking was 0.47, with significant difference (p<0.05). Conclusion: EMG data was higher in stair walking than over-ground walking. However, in the comparison of symmetry ratio, asymmetric EMG of quadriceps femoris was significantly increased during stair walking. These findings suggested that application of stair walking for strengthening of both legs can be positive, but the key factor is maintaining asymmetrical posture of both legs. Therefore, physical therapists should make an effort to reduce asymmetry of quadriceps femoris power during stair walking by stroke patients.

• 한국전문물리치료학회지
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• 제16권3호
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• pp.24-31
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• 2009

This study aimed to investigate the effect of differing heel heights on the electromyographic (EMG) activity in vastus medialis (VM) and vastus lateralis (VL) during stair ascending and descending activities. A total of 26 healthy women volunteered to perform stair-ascending and stair-descending tasks with 3 heel heights: barefoot, 3 cm, and 7 cm. The EMG activities of the VM and VL were recorded during the tasks. During the stair ascending and descending tasks, the EMG activities of both VM and VL significantly changed with differing the heel heights (p<.05). Moreover, the EMG activities of VM and VL during the stair ascending task were significantly higher than the corresponding values during the stair-descending task (p<.05). However, there were no significant differences between the VM:VL EMG ratios for the 3 heel heights (p>.05). The VM:VL EMG ratios between the 2 tasks differed significantly in the 7 cm high heel condition (p<.05). Despite an increase in the EMG activities in both VM and VL during stair ascending and descending tasks, there was no change in the relative EMG intensities of VM and VL, which was measured by calculating the VM:VL ratio this result indicates that no VM:VL imbalances were elicited. The relative EMG intensities of VM and VL during stair descent were lower than the corresponding values during the ascent, suggesting that VM and VL may show an imbalance in the eccentric activation during the weight-acceptance phase. This study provides useful information that will facilitate future research on how heel height affects muscle activity around the knee joint.

• 한국전문물리치료학회지
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• 제20권4호
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• pp.55-64
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• 2013

The first purpose was to identify the plantar pressure distributions (peak pressure, pressure integral time, and contact area) during level walking, and stair ascent and descent in asymptomatic flexible flatfoot (AFF). The second purpose was to investigate whether peak pressure data during level walking could be used to predict peak pressure during stair walking by identifying correlations between the peak pressures of level walking and stair walking. Twenty young adult subjects (8 males and 12 females, age $21.0{\pm}1.7$ years) with AFF were recruited. A distance greater than 10 mm in a navicular drop test was defined as flexible flatfoot. Each subject performed at least 10 steps during level walking, and stair ascent and descent. The plantar pressure distribution was measured in nine foot regions using a pressure measurement system. A two-way repeated analysis of variance was conducted to examine the differences in the three dependent variables with two within-subject factors (activity type and foot region). Linear regression analysis was conducted to predict peak pressure during stair walking using the peak pressure in the metatarsal regions during level walking. Significant interaction effects were observed between activity type and foot region for peak pressure (F=9.508, p<.001), pressure time integral (F=5.912, p=.003), and contact area (F=15.510, p<.001). The regression equations predicting peak pressure during stair walking accounted for variance in the range of 25.7% and 65.8%. The findings indicate that plantar pressures in AFF were influenced by both activity type and foot region. Furthermore the findings suggest that peak pressure data during level walking could be used to predict the peak pressure data during stair walking. These data collected for AFF can be useful for evaluating gait patterns and for predicting pressure data of flexible flatfoot subjects who have difficulty performing activities such as stair walking. Further studies should investigate plantar pressure distribution during various functional activities in symptomatic flexible flatfoot, and consider other predictors for regression analysis.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1995년도 추계학술대회논문집
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• pp.87-90
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• 1995

Biomechanical can physchological approaches have provided the optimum stair dimensions but physiological approach has never been used in assessing the common method of assessing the optimum stair dimension. Therefore, this study was conducted to investigate the validity of the physiological measure of heart rate in assessing the optimum stair dimensions. Sixteen subjects were asked to walk up three different stairs with their normal walking speed. The results showed that the physiological approach with the heart rate difference was found to be valid in assessing the optimum stair dimension. The optimum stair dimension from this study (riser length for 185 mm and tread length for 310 mm) was chosen because it was similar to optimum dimension by the psychological approach (Irvine et al., 1990).

• 한국운동역학회지
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• 제18권1호
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• pp.169-178
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• 2008

본 연구는 계단 보행 중 연속적인 두 스텝의 3차원적 지면반력 파라미터를 제공하고, 계단의 너비에 따른 지면 반력 파라미터의 차이 및 비대칭성과 일관성을 규명하는데 있다. 10명의 성인 대상자가 본 실험에 참여하였으며, 각 10번의 평지, 상향 및 하향보행을 3가지의 다른 너비의 계단에서 실시하였다. 본 연구를 수행한 결과 다음과 같은 결론을 얻었다. 첫째, 계단의 너비는 대부분의 지면반력 파라미터들의 패턴이나 일관성, 비대칭지수에 영향을 미치지 않았다. 둘째, 평지 보행과 계단보행은 지면반력 파라미터의 패턴에서 큰 차이를 보였다. 평지보행과 상향보행은 Fz1, Fz2, 그리고 Fz3로 구성되는 "M" 형태를 보인 반면에 하향보행에서는 Fz2가 거의 없고 큰 Fz1과 작은 Fz3로 구성된 패턴을 보였다. 또한 계단 보행은 평지보행과 매우 다른 전 후 지면반력 패턴을 보였다. 즉 상향보행은 Fy1이 존재하지 않는 패턴을, 하향보행은 Fy2가 존재하나 매우 작은 크기를 보였다. 셋째, 계단보행의 수직 지면반력 파라미터들은 적용가능한 일관성 지수 및 비대칭 지수를 나타내었다.

• 한국생산제조학회지
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• 제26권1호
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• pp.89-99
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• 2017

This paper describes the development of a thigh wearable robot for power assistance during stair climbing. In the wearable robot developed in this study, high-power BLDC motors and high-capacity harmonic reduction gears are used to effectively assist the thigh muscle during stair climbing. In particular, normal ground and stair are distinguished accurately by using wireless smart shoes, and the stair climbing assistance is performed by activating the actuators at an appropriate time. Impedance of the hip joint was effectively reduced by performing friction compensation of the gears, and a wearing adjustment mechanism was designed to fit the robot to the thigh by conveniently modifying the width and tilting angle of the robot using set collars. Consequently, the performance of the developed thigh wearable robot was verified through stair climbing experiments with EMG measurement.

• 한국운동역학회지
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• 제18권4호
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• pp.161-169
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• 2008

이 연구는 성인 남성을 대상으로 계단 너비에 따른 계단 보행의 지지국면 시 하지분절의 역학적 변인을 정량적으로 분석하여, 보다 효과적인 계단의 너비를 제시하고자 실시하였으며, 이를 위해 20대의 남자 대학생 10명이 참여하였다. 계단의 높이는 18cm, 최소폭은 90cm로 동일하나 디딤면의 너비가 각각 26cm, 31cm, 36cm인 세 개의 계단을 사용 하였다. 이때 사용된 계단의 세 번째 디딤면에 지면반력기를 설치하여 지지구간의 하지관절 모멘트를 분석한바 다음과 같은 결론을 얻었다. 상향계단보행에서 발목관절의 굴곡/신전 모멘트변화를 분석한 결과 계단의 너비가 증가 할수록 pull-up 단계의 peak 모멘트가 감소하였으며(p<.05), 무릎관절에서는 굴곡/신전 모멘트를 분석한 결과 계단의 너비가 증가할수록 무릎에 작용하는 신전모멘트가 중지지기에 증가하는 것으로 나타났다(p<.05). 그러나 고관절에서 차이가 없는 것으로 나타났다. 그리고 하향계단보행에서 발목관절의 굴곡/신전 모멘트를 분석한 결과 계단의 너비가 증가할수록 지지기 동안 저측굴곡과 배측굴곡의 차이가 확연히 나타나는 것으로 나타났으며(p<.05), 무릎관절과 고관절에서는 굴곡/신전 모멘트를 분석한 결과 계단의 너비에 따라 신전 모멘트의 차이가 크지 않은 것으로 나타났다.

• 한국화재소방학회논문지
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• 제25권1호
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• pp.1-6
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• 2011

고층건축물에서의 피난효율과 수용인원 산정기준의 문제점을 확인하기 위하여 피난 시뮬레이션을 수행하였다. 지상 39층 주상복합 건축물의 계단폭이 각각 1.2m, 1.5m, 1.8m일 때, 피난시간과 피난자수를 Simulex로 계산하였다. 소방법 기준으로 산정한 총수용인원은 실거주자의 2.3배, NFPA 101 인명구조코드 기준의 2.6배였다. 소방법 기준의 경우, 계단폭이 작을수록 증간층에서의 병목현상으로 인해 피난효율이 낮았지만, 실거주나 NFPA 기준에서는 피난효율이 높고 계단폭이 피난효율에 미치는 영향이 미미함을 확인하였다. 소방법 기준을 적용할 때 계단폭이 1.8m에서도 병목현상이 일어나지만, 실거주 또는 NFPA 기준을 적용할 때는 계단폭 1.2m에서도 안전한 것으로 나타 남에 따라 수용인원 산정관련 소방법 기준의 완화가능성에 대한 추가연구가 필요하다.

• 전자공학회논문지B
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• 제32B권10호
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• pp.1269-1279
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• 1995

A mobile robot in a nuclear power plant is usually needed to equip the ability of going up and down stairs for a some kind of inspection. For this purpose, it is necessary for the mobile robot to figure out the size of stairs laid on a navigation path to gurantee robot's moving freely. In this paper, to measure the size of stairs existing in front of a mobile robot we designed the stair size recognition unit which can measure the stair's height and width using an ultrasonic sensor and/or a CCD camera. Also to obtain higher reliability of ultrasonic sensing data we proposed the horizontal sensing method. On the assupmtions that the mobile robot generates a trajectory while ascending stairs, we simulated it on a IBM compatible computer. The result showed that the suggested method satisfied our purpose. In a stair size estimation, the detected stair's height error was about .+-.3mm, and width was about .+-.5mm.