• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2271-2274
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• 2005

The desired ZMP is different from the actual ZMP of a humanoid robot during actual walking and stand upright. A humanoid robot must maintain its stable posture although external force is given to the robot. A humanoid robot can know its stability with ZMP. Actual ZMP may be moved out of the foot-print polygons by external disturbance or uneven ground surfaces. If the position of ZMP moves out of stable region, the stability can not be guaranteed. Therefore, The control of the ZMP is necessary. In this paper, ZMP control algorithm is proposed. Herein, the ZMP control uses difference between desired ZMP and actual ZMP. The proposed algorithm gives reaction moment with ankle joint when external force is supplied. 3D simulator shows motion of a humanoid robot and calculated data.

• The Journal of Korean Physical Therapy
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• 제21권3호
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• pp.53-59
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• 2009

Purpose: The purpose of this study was to investigate the effects of proprioceptive exercise on the body alignment of elderly women. Method: The experimental group consisted of twenty elderly women who participated in proprioceptive exercise for 8 weeks. The subjects were measured using Global Posture System equipment for assessing their body alignment. Body alignment was measured at the ear, shoulder joint, knee joint and calcaneocuboid joint on the sagittal plane, and the left and right acromion process positions, the ASIS and the medial malleoulus on the coronal plane. The body alignment data was used to assess the changes before and after proprioceptive exercise. The data of the experimental group was compared and analyzed using the Wilcoxon singed-rank test between before and after proprioceptive exercise. The Mann-Whithney test was used to compare the experimental group and the control group. Result: The result of this study was that the body alignment of the experimental group at the ear and knee joint on the sagittal plane was significantly in alignment with the line of gravity (p<0.05) before and after proprioceptive exercise. The body alignment was statistically different (p<0.05) between the experimental group and the control group on the frontal plane and sagittal plane. Conclusion: This study showed that proprioceptive exercise does affect the body alignment in elderly women. This indicates that there is interaction that plays a crucial role for proprioceptive stimuli and the body alignment.

• 대한족부족관절학회지
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• 제17권2호
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• pp.121-129
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• 2013

Purpose: To evaluate the radiographic characteristics of the tarsometatarsal osteoarthritis with hallux valgus deformity and report the clinical results of the operative treatment. Materials and Methods: This is a retrospective study of 20 patients, 22 feet who had been operated for non-traumatic tarsometatarsal osteoarthritis with hallux valgus (TMT group) and control group of hallux valgus patients without tarsometatarsal osteoarthritis (26 patients, 28 feet) from April 2004 to July 2011. Radiographic characteristics were compared between the groups, using hallux valgus angle, $1^{st}-2^{nd}$ intermetatarsal angle, metatarsal length ratio, metatarsus adductus angle, talonavicular coverage angle, talus-$1^{st}$ metatarsal angle, calcaneal pitch angle and medial cuneiform height. Pre- and postoperative difference of $1^{st}-2^{nd}$ metatarsal declination angle and distance between the $1^{st}-2^{nd}$ metatarsal head were evaluated. The clinical results were evaluated by American Orthopaedics Foot and Ankle Society (AOFAS) midfoot scale and visual analogue scale (VAS). Results: Metatarsal length ratio was significantly larger in TMT group (p<0.001). Metatarsus adductus angle, talonavicular coverage angle, talus-$1^{st}$ metatarsal angle on lateral radiograph, calcaneal pitch angle and medial cuneiform height were different from control group (p<0.001, p<0.001, p=0.001, p=0.010, p=0.006). Postoperative declination of the $2^{nd}$ metatarsal and distance between the $1^{st}-2^{nd}$ metatarsal head were increased (p=0.009, p=0.001). The AOFAS and VAS score were improved (p<0.001, p<0.001). Conclusion: Non-traumatic osteoarthritis of the tarsometatarsal joints seems to be associated with long 2nd metatarsal length, metatarsus adductus and flatfoot deformity. Spur excision may be successful to relieve symptoms when the arthritis was diagnosed in early stage.

• 대한의용생체공학회:의공학회지
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• 제33권2호
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• pp.98-103
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• 2012

The purpose of this study was to compare premotor time(PMT) and electro-mechanical delay(EMD) between sitting and standing posture. Twenty four healthy young subjects(12 women and 12 men) participated in this study. Subjects were instructed to perform maximal, voluntary, isometric contraction of ankle muscle(tibialis anterior and gastrocnemius muscles) in reaction to auditory stimulus. PMT and EMD, calculated from stimulus, EMG and torque profile were compared between sitting and standing postures. As statistical analysis, paired t-test was performed to assess difference between sitting and standing posture. In both tibialis anterior and gastrocnemius muscles, EMD was found to be significantly longer for standing than sitting. However, PMT in standing posture was longer than that in sitting posture only in gastrocnemius muscles. These result indicate that increased reaction time, particularly, increased EMD of ankle muscles in standing posture may be caused by co-contraction of ankle muscles for postural control in standing posture.

• 한국운동역학회지
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• 제27권3호
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• pp.171-179
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• 2017

Objective: The purpose of this study was to perform a kinematic and kinetic analysis of double-under jump rope technique according to skill level and sex. Method: Participants comprised a skilled group of 16 (9 males, 7 females), and an unskilled group of 16 with 6 months or less of experience (9 males, 7 females). Five consecutive double-under successes were regarded as 1 trial, and all participants were asked to complete 3 successful trials. The data for these 3 trials were averaged and analyzed after collecting the stable third jump in each trial. The variables used in the analysis included phase duration, total duration, flight time, vertical toe height, stance width, vertical center of mass displacement, and right lower limb ankle, knee, and hip joint angles in the sagittal plane during all events. Results: The skilled group had a shorter phase and total duration and a shorter flight time than the unskilled group. The vertical center of mass displacement and ankle dorsiflexion angle were significantly smaller in the skilled group. The male group had a shorter phase duration than the female group. The vertical toe height was greater, the stance width was smaller, and the ankle and hip flexion angles were smaller in the male group. Conclusion: Variables that can be used to distinguish between skill levels are phase and total duration, flight time, vertical center of mass displacement, and ankle dorsiflexion angle. Differences between sexes in double-under jump rope technique may be related to lower limb flexion angle control.

• 대한인간공학회지
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• 제26권2호
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• pp.131-136
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• 2007

In this study, we developed an active ankle-foot orthosis(AAFO) which can control dorsi/ plantar flexion of the ankle joint to prevent foot drop and toe drag during walking. 3D gait analyses were performed on five healthy subjects under three different gait conditions: the normal gait without AFO, the SAFO gait with the conventional plastic AFO, and the AAFO gait with the developed AFO. As a result, the developed AAFO preeminently induced the normal gait compared to the SAFO. Additionally, AAFO prevented foot drop by proper plantarflexion during loading response and provided enough plantarflexion moment as a driving force to walk forward by sufficient push-off during pre-swing. AAFO also could prevent toe drag by proper dorsiflexion during swing phase. These results indicate that the developed AAFO may have more clinical benefits to treat foot drop and toe drag, compared to conventional AFOs, and also may be useful in patients with other orthotic devices.

• 대한통합의학회지
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• 제12권3호
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• pp.155-161
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• 2024

Purpose : Wearing high-heeled shoes leads to foot and ankle instability, which requires leg muscles to remain in constant contraction. In order to adapt to the instability of the feet and ankles caused by wearing high heels, the muscles of the legs continuously repeat contraction and relaxation. Previous studies of the impact of stair climbing in high-heeled shoes have involved placing the entire stepping area of the shoe on the stair. However, high-heeled shoe wearers sometimes unconsciously contact the stair using only half of the stepping area. Therefore, the objective of this study was to examine differences in leg and ankle muscle activation according to stepping area during stair climbing in high-heeled shoes. Methods : Twenty young women in their early 20s voluntarily agreed to participate in this study. We used surface electromyography to measure gastrocnemius and tibialis anterior activation in the right leg during stair climbing under three conditions: barefoot, using half of high-heeled shoe stepping area, and using the total of high-heeled shoe stepping area. Barefoot, half of high heeled shoe, and total of high-heeled shoe were used to evaluate the effects of different areas of the foot or high heels touching the stairs. Results : Both muscles showed significant activity differences among the three stair climbing conditions. Gastrocnemius activity was significantly different between the high-heeled shoe conditions (p= .032), and tibialis anterior activity was significantly different between barefoot stair climbing and climbing with half of the high-heeled shoe stepping area (p= .021). Conclusion : The stepping area increased as heel size increased, thus increasing excessive gastrocnemius and tibialis anterior activity to control excessive ankle joint movement. We infer that using half of the high-heeled shoe stepping area prevents muscle fatigue by reducing excessive leg and ankle muscle activation.

• 대한족부족관절학회지
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• 제23권4호
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• pp.173-182
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• 2019

Purpose: This study determined if anterior talofibular ligament (ATFL)/superior extensor ankle retinaculum (SEAR) thicknesses are related to dynamic balance in individuals with chronic ankle instability (CAI). Materials and Methods: The subjects were 14 males and 15 females (age=24.52±3.46 years). Ankle instability was assessed using the Cumberland Ankle Instability Tool (CAIT) with a cut off score of 25 to define two groups. SonoSite MTurbo (Fugifilm Sonosite, Inc.) musculoskeletal ultrasound (MSKUS) unit was used to assess ATFL and SEAR thicknesses. Dynamic balance was measured with the Y Balance Test (YBT) and two NeuroCom balance tests. Results: There were no significant differences in the average ATFL thickness between stable and unstable ankles in those subjects with CAI (0.25±0.03 cm and 0.21±0.05 cm, respectively) or in the SEAR thickness (0.09±0.04 cm and 0.10±0.03 cm, respectively). There were also no significant differences in the right and left ATFL thicknesses (0.23±0.07 cm and 0.21±0.04 cm, respectively) or the SEAR thicknesses (0.09±0.01 cm and 0.09±0.01 cm, respectively) in those without CAI. There were no differences between limbs in composite scores on YBT in those with CAI (p=0.35) and those without CAI (p=0.33). There was a moderate correlation between the left SEAR thickness and the large forward/backward perturbations on the NeuroCom (Natus) motor control test (r=0.51, p=0.006 and r=0.54, p=0.003, respectively). Conclusion: There were no differences in the ATFL/SEAR thicknesses or balance measures between or within the groups, likely because CAI is multi-factorial and related to mechanisms other than tissue changes alone. More sensitive technology and a better definition of the measurement process may provide more definitive results.

• 대한관절경학회지
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• 제4권2호
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• pp.148-153
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• 2000

목적 : 관절경하 족근관절 고정술의 결과를 분석하여 그 유용성을 보고하고자 한다. 대상 및 방법 : 1992년 10월부터 1996년 8월까지 족근관절 동통으로 관절경하 족근관절 고정술을 시행받은 5명, 6례를 대상으로 하였으며, 3례는 류마토이드 관절염, 2례는 퇴행성 관절염 그리고 1례는 결핵성 관절염이었다. 연령은 최저 38세에서 최고 65세로 평균 48세였으며, 남자 1명, 여자 4명이었다. 추시기간은 최단 12개월에서 최장 80개월로 평균 45개월이었다. 수술 방법은 경골과 종골의 외측부에 외고정장치를 부착하여 신연시킴으로써 족근관절강을 넓게 하여 관절경 및 수술기구를 사용할 수 있는 공간을 확보하였으며 전외측, 전내측 및 전면중앙의 입구를 사용하였다. shaver와 burr를 사용하여 경골, 거골 및 비골의 관절연골 및 연골하 뼈의 일부를 제거하고 출혈을 확인하였으며 경골 내과 및 비골 외과 상방에서 $2\~3$개의 유관나사(cannulated screws)를 사용하여 압박 고정하였다. 술 후 $6\~12$주간 단하지 석고 고정을 시행하였다. 결과 : 전례에서 족근관절의 유합소견을 보였으며 방사선 사진상 골유합의 시기는 최단 6주에서 최장 15주로 평균 10주였고 합병증은 발생하지 않았다. 결론 : 관절경하 족근관절 고정술은 류마토이드 관절염, 퇴행성 관절염 및 비교적 관절에 국한된 감염이 있는 환자에서 족근관절 고정술이 적응이 될 시 사용할 수 있는 좋은 방법으로 사료된다.

• 근관절건강학회지
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• 제10권1호
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• pp.62-76
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• 2003

This study was a quasi-experimental study of non-equivalent control group pretest and posttest design. The purpose of this study was to determine the effect of Tai Chi exercise program on physical functions, psychological functions, and fall among the fall-prone elderly. The data were collected from September 19, 2001 to January 31, 2002. The study, conducted at two facilities located in Kwang-ju, was targeted to the ambulatory aged 60 years or older who had at least one of the key fall risk factors. Experimental group participated in Tai Chi exercise for 40 minutes per one time and three times a week for 12weeks at an auditorium. Fifty nine fall-prone elderly were assigned to 12-week Tai Chi exercise program (n=29) and control group (n=30). They underwent tests of lower muscle strength, time for chair stand, balance, flexibility, depression, falls efficacy, fear of falling, and numbers of fall at the baseline and at the 12th week. Numbers of fall and fall injuries were monitored for 16 weeks(12-weeks intervention plus 4-week follow-up periods) using fall calendar. Each participant was given a calendar to record the numbers of fall per day for a month. The calendars were collected at the last week of each month. 1. Tai Chi exercisers showed significant improvement in the strength of knee flexors, and ankle dorsiflexors and plantarflexors compared to the control group. The experimental group had improvement in the strength of knee extensors while the control group did not, with no statistical significance. 2. Tai Chi exercisers reported positive change in the average time of chair stand as compared to the control group. 3. Tai Chi exercisers had significant improvement in flexibility as compared to the control group. 4. There was no significant difference in the depression between the two groups, even though the Tai Chi exercisers maintained depression score in the same level while the others were increased. 5. Tai Chi exercisers showed significant improvements in the falls efficacy as compared to the control group. The falls efficacy was significantly improved among the experimental group while the opposite was identified among the control group. 6. The experimental group reported the significant reduction of the fear of fall, whereas control group reported the opposite. 7. Of the 59 subjects for 16weeks(12weeks intervention period and 4weeks follow up), 9 (31.0%) of the 29 in exercise group and 15 (50%) of the 30 in the control group fell (relative risk=0.62. 95% CI 0.32-1.19), even with no statistical difference. The results suggest that the Tai Chi exercise program can improve the strength of knee flexors, ankle dorsiflexors and plantarflexors, chair stand. flexibility, falls efficacy, and fear of falling for the fall-prone elderly.