• Journal of Institute of Control, Robotics and Systems
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• v.16 no.10
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• pp.948-956
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• 2010

The purpose of this study was to test the effectiveness of a prototype KAFO (Knee-Ankle-Foot Orthosis) powered by two artificial pneumatic muscles during walking. We had previously built powered AFO (Ankle-Foot Orthosis) and KO (Knee Orthosis) and used it effectively in studies on assistance of plantaflexion and knee extension motion. Extending the previous study to a KAFO presented additional challenges related to the assistance of gait motion for rehabilitation training. Five healthy males were performed gait motion on treadmill wearing KAFO equipped with artificial pneumatic muscles to power ankle plantaflexion and knee extension. Subjects walked on treadmill at 1.5 km/h under four conditions without extensive practice: 1) without wearing KAFO, 2) wearing KAFO with artificial muscles turned off, 3) wearing KAFO powered only in plantaflexion under feedforward control, and 4) wearing KAFO powered both in plantaflexion and knee extension under feedforward control. We collected surface electromyography, foot pressure and kinematics of ankle and knee joint. The experimental result showed that a muscular strength of wearing KAFO powered plnatarfexion and knee extension under feedforward control was measured to be lower due to pneumatic assistance and foot pressure of wearing KAFO powered plnatarfexion and knee extension under feedforward control was measured to be greater due to power assistance. In the result of motion analysis, the ankle angle of powered KAFO in terminal stance phase was found a peak value toward plantaflexion and there were difference of maximum knee flexion range among condition 2, 3 and 4 in mid-swing phase. The current orthosis design provided plantaflexion torque of ankle jonit in terminal stance phase and knee extension torque of knee joint in mid-swing phase.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.4
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• pp.163-174
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• 2020

PURPOSE: This study examined the effects of Robot Tilt-table Training (RTT) on the lower extremity strength, balance, gait, and satisfaction with rehabilitation, in patients with subacute stroke (less than six months after stroke onset), and requiring intensive rehabilitation. METHODS: A total of 29 subacute stroke patients were divided into an RTT group (n = 14) and a Body Weight Support Treadmill Training (BWSTT) group (n = 15). The mean age of patients was 62 years. RTT and BWSTT were performed for four weeks, three times a week, for 30 minutes. Isometric strength of the lower extremities before and after intervention was compared by measuring the maximal voluntary isometric contraction of the lower extremity muscles. To compare the balance function, the center of pressure (COP) path-length and COP velocity were measured. Timed Up & Go test (TUG) and 10 Meter Walking Test (10 MWT) were evaluated to compare the gait function. A satisfaction with rehabilitation survey was conducted for subjective evaluation of the subject's satisfaction with the rehabilitation training imparted. RESULTS: In the intra-group comparison, both groups showed significant improvement in lower extremity strength, balance, gait, and satisfaction with rehabilitation, by comparing the parameters before and after the intervention (p < .05). Comparison of the amount of change between groups revealed significant improvement for all parameters in the RTT group, except for the 10 MWT (p < .05). CONCLUSION: Both groups are effective for all variables, but the RTT group showed enhanced efficacy for variables such as lower extremity strength, balance, gait, and satisfaction with rehabilitation, as compared to the BWSTT group.

• The Journal of the Society of Stroke on Korean Medicine
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• v.14 no.1
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• pp.40-48
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• 2013

■ Objectives This study was designed to investigate the effects of an ankle foot orthosis(AFO) on gait of two hemiparetic stroke patients with foot drop. ■ Methods Gait of two hemiparetic stroke patients were analyzed during walking on the treadmill without or with AFO application. The spatiotemporal and center of pressure(CoP) intersection parameters of gait analysis were measured using a treadmill gait analysis system. ■ Results The AFO had positive effects on hemiparetic gait parameters; increasing cadence, increasing step length, decreasing step time, stride time, and lateral symmetry. ■ Conclusion Hemiparetic gait was improved by ankle foot orthosis.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.2
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• pp.127-137
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• 2011

We have developed a wearable device that can convert sensor data into real-time step counts and activity levels. Sensor data on gait were acquired using a triaxial accelerometer. A test was performed according to a test protocol for different walking speeds, e.g., slow walking, walking, fast walking, slow running, running, and fast running. Each test was carried out for 36 min on a treadmill with the participant wearing a portable gas analyzer (K4B2), an Actical device, and the device developed in this study. The signal vector magnitude (SVM) was used to process the X, Y, and Z values output by the triaxial accelerometer into one representative value. In addition, for accurate step-count detection, we used three algorithms: an heuristic algorithm (HA), the adaptive threshold algorithm (ATA), and the adaptive locking period algorithm (ALPA). A regression equation estimating the energy expenditure (EE) was derived by using data from the accelerometer and information on the participants. The recognition rate of our algorithm was 97.34%, and the performance of the activity conversion algorithm was better than that of the Actical device by 1.61%.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.109-114
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• 2008

The purpose of this study was to estimate the energy expenditure simply and practically during physical activities. The physical activity is quantified by the integration of the accelerometer signals obtained from the triaxial accelerometer attached at the waist level of the human body. To find a relationship between energy expenditure and accelerometer data, 6 male and 5 female subjects walked and ran on the treadmill with speeds of 1.5, 3.0, 4.5, 6.0, 6.5, 7.0, and 8.5 km/hr. Each subject performed walking at the speed lower than 6.0 km/hr and running at the speed higher than 6.5 km/hr. Actual energy expenditure was determined by a continuous direct gas analyzer. Two predictive equations of walking and running mode for energy expenditure which includes gender, body mass index(BMI) and data from accelerometer were developed using multiple regression analysis. The correlation coefficients and coefficients of determination between the estimated and measured energy expenditure were R=0.936, R2=0.876 and R=0.881, R2=0.776 in walking and running mode, respectively. For further study, experiments on a larger scale of test subjects are essential for acquiring more reliable results.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.179-186
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• 2009

This works studied to compare gas analyzer with accelerometer and the estimation of energy expenditure based on different attaching position of tri-axial accelerometer such as waist and top of the foot Based on the fact that oxygen intake increases more radically linearly during walking more than 8.0km/hr. 9 male subjects performed walking and running on the treadmill with speed of $1.5{\sim}8.5km$/hr and $4.5{\sim}13.0km$/hr, respectively. Commercially available Nike + iPod Sports kit was used to compare energy expenditure with sensor module attached to their foot. Actual energy expenditure was determined by a continuous direct gas analyzer and two multiple regression equations of walking and running mode for different attaching position were developed. Results showed that estimation accuracy of energy expenditure using waist mounted accelerometer was higher than that of the top of the foot and Nike + iPod Sports kit. Results of energy expenditure based on waist and top of the foot showed that the crossover state of energy expenditure occurred at 7.5km/hr. But Nike + iPod Sports kit could not find intersection of energy expenditure in all nine subjects. Therefore the sensor module attached to the waist and separate multi regression equation by walking and running mode was the best to estimate more accurate prediction.

• Fashion & Textile Research Journal
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• v.13 no.6
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• pp.943-951
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• 2011

The purpose of this study is to analyze the physiological effects of non-elastic corset on women's health and pain through measuring the clothing pressure, subjective pressure sensation, blood velocity and metabolism. 5 women in their twenties were picked as our subjects, their average size being 85cm at bust girth, 69 cm at waist girth. With the subjects each wearing a corset, we are testing in artificial environment with a treadmill according to the planned exercise procedures. The average pressure of the corset is 0.938 kPa (maximum 3.006 kPa at 45 degree front bowing), which is 10.2 times higher than the control group, averaging from 9.3 times higher at resting, 11.4 times at walking, 11.1 times at running. The effect of corset pressure on the physiological responses of the body is increased more when exercise than when resting. Clothing pressure increased in the order of the postures: sitting > standing with 45 degree bowing > standing. They experienced a high level of tighten discomfort of 5.6 in the scale of 1.0 to 7.0 due to the high pressure of the corset when resting, after intense exercise the level increased to 6.0, while without corset the level increased 1.7 to 2.2. With corset on, the blood circulation did not increase even though when the body exercised and blood flow became unbalanced making great gaps between both at the right and left finger tips. Perspiration of chest and back decreased 37.3% when wearing corset; 27.5% at resting, 56.7% at walking, 25.8% at running, and 39.0% at recovery. With corset on oxygen consume and metabolism increased 9.0%, 7.9%, respectively, which means the corset makes the body uncomfortable. Lung volume exchange VE decreased almost 4.1~7.3% with corset on and $VCO_2/VO_2$, RER and total volume in lung, VT also decreased too, which means the digestion of stomach and lung function are inhibited due to the high corset pressure.

• The Journal of Korean Physical Therapy
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• v.11 no.2
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• pp.43-50
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• 1999

The purpose of this study was to evaluate the change of the energy consumption when loading to leg of the 60persons who don't have past history of cardiopulmonary and neuromuscular disease, To evaluate the change or energy consumption, heart rate was measured in sitting position for 5minute, during walking for 3minute at for 4.8km on treadmill, and during resting state after walking with 1Kg loading to right ankle, and the other 1Kg loading was added to left ankle and then heart rates were measured in the The results were as follow; 1. PCI value without loading to Ankle were significantly increased compared to 1Kg, and 2Kg. (p<0.05) 2. Female Subjects showed mon increased PCI value in without leading and 2Kg loading compared to male subjects. ( p<0.05) 3. When 1Kg ana 2Ka loading to ankle significantly differences were showed between them. (p<0.05) 4. In the case of 1Kg and 2Kg loading, the difference among age groups was observed and the significant difference among PCI, PCI 1kg, PCI 2kg was showed in the only group that is less than 30 years old. 5. In every PCI condition the difference among height groups was observed and the significant difference among PCI conditions was showed in the only group that is less than 165cm. 6. The difference among weight groups in each PCI condition was not observed, but the significant differences among PCI conditions was showed in every group except the group that h from 60kg to 69kg. These results showed that energy consumption was increased according to loading on the ankle during Sate so weight of orthosis or prosthesis met be considered when choosing them and during gait training with these ones.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.101-113
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• 2016

Objective: The purpose of this study was to investigate the effect of leg length discrepancy (LLD) on the human body during gait and standing posture. Methods: The study group comprised of 17 adult participants with LLDs of <1 cm. LLDs were artificially induced to 0, 1, 2, and 3 cm. The proportion of weight distribution, shift of the mean center of pressure, and Cobb's angle were measured in the standing position. Kinematic variables such as walking and striding width and time, and the proportion of stance phase for single- and double-limb gait were measured as well. The participants were required to either stand or walk on a treadmill (Zebris FDM) with a pressure plate, and the Cobb's angle measurements were obtained from radiographs. Results: A discrepancy of 3 cm in leg length resulted in a statistically significant shift of the center of pressure in the standing position. Moreover, the Cobb angle increased as the discrepancy became larger. The step length and width of the longer (left) leg during gait statistically significantly increased when the discrepancy was 2 cm. In addition, step time was statistically significant when the discrepancy between the longer (right) and shorter (left) legs was more than 2 cm. The proportion of single-limb stance phase was statistically significant as the discrepancy became larger, especially when the discrepancy was >2 cm for the longer (right) leg and 1 cm for the shorter (right) leg. Conclusion: The study showed that LLD influenced deformations of the human body and walking.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.5
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• pp.631-638
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• 2012

This work proposes a new method to generate velocity profile of a traction motor equipped in a rehabilitation system for knee joint patients through humanoid robot simulation. To this end, a three-dimensional full-body humanoid robot model is newly constructed, and natural human gait is simulated by applying to it reference joint angle trajectories already published. Linear velocity is derived from distance data calculated between the positions of a thigh band and its traction motor at every sampling instance, which is a novel idea of this paper. The projection rule is employed to kinematically describe the humanoid robot because of its high efficiency and accuracy, and measured joint trajectories are used in simulating human natural gait referring to Winter's book. The attained motor velocity profile for a certain position in human body will be applied to our walking-assistance system which is implemented with a treadmill system.