• Korean Journal of Applied Biomechanics
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• v.33 no.3
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• pp.85-93
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• 2023

Objective: This study examined differences in joint kinematics and movement variability of lower extremity between adolescent athletes with and without lateral ankle sprain (LAS) history during drop vertical jump. Method: Fourteen adolescent athletes with LAS history and 14 controls participated in this study. The independent variable was group while dependent variables were 3D joint kinematics and movement variability of hip, knee, and ankle joint. Ensemble curve analyses were conducted to identify differences in movement strategies between two groups. Results: The LAS group showed that greater eversion during jump phase compared with the control group. Additionally, less movement variability was found in the LAS group during the pre-landing and jump phases in ankle and hip joints compared with the control group. Conclusion: The LAS group may adapt the environmental constraints by reducing the movement variability in ankle and hip joints. However, training programs focusing on recovery of ankle function should be emphasized after LAS because excessive pronation for prevention of LAS during the jump phase may result in reduced performance.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.175-187
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• 2006

The purpose of this study was to find the relationship between Achilles tendon angle, angular velocity from 2D cinematography utilized to easily analyze the functions of shoes, ankle joint moment, knee joint moment, and hip joint moment from 3D cinematography utilized to predict the injury. Also, this study was to provide the optimal standard to analyze the injury related to the shoes. Subjects in this study were 30 university male students and 18 conditions (2 types of running speed, 3 of midsole hardness, 3 of midsole height) were measured using cinematography and force platform. The results were as following. 1) Hip joint abduction moment was effected by many variables such as running speed, midsole height, maximum achilles tendon angle, ground reaction force. 2) Knee joint rotational moment in running was approximately 1/10 - 1/4 times of the injury critical value and eversion moment was approximately 1/4 - 1/2 times of the injury critical value. 3) Ankle joint pronation moment in running was 1/3 - 1/2 times of the injury critical value. 4) Knee joint rotational moment was found to be irrelevant with maximum achilles tendon angle or angular velocity. 5) Pronation from running was thought to be relevant to rather eversion moment activity than rotational moment activity of knee joint. 6) Plantar flexion abductor of ankle showed significant relationship with the ground reaction force variable. 7) When the loading rate for ground reaction force in passive region increased, extensor tended to be exposed to the injury. Main variables in biomechanical analysis of shoes were impact absorption and pronation. Among these variables, pronation factor was reported to be relevant with knee injury from long duration exercise. Achilles tendon angle factor was utilized frequently to evaluate this. However, as the results of this study showed, the relationship between these variables and injury relating variable of knee moment was so important. Studies without consideration on this finding should be reconsidered and reconfirmed.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.4
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• pp.305-313
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• 2016

Movements of the lower limb are important for normal walking and smooth oscillation of the center of gravity. The ankle rotations such as dorsi-flexion, plantar-flexion, inversion and eversion allows the foot to accommodate to ground during level ground walking. Current below knee (B/K) prostheses are used for replacing amputated ankle, and make it possible for amputees to walk again. However, most of amputees with B/K prostheses often experience a loss of terrain adaptability as well as stability because of limited ankle rotation. This study is focused on the development of multi-rotational prosthetic foot for lower limb amputee. Our prosthesis is possible for amputees to easily walk in level ground by rotating ankle joint in sagittal plane and adapt to the abnormal terrain with ankle rotation in coronal plane. The resistance of ankle joint in the direction of dorsi/plantar-flexion can be manually regulated by hydraulic damper with controllable nozzle. Furthermore, double layered rubber induce the prosthesis adapt to irregular ground by tilting itself in direction of eversion and inversion. The experimental results highlights the potential that our prosthesis induce a normal gait for below knee amputee.

• Korean Journal of Applied Biomechanics
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• v.33 no.2
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• pp.62-72
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• 2023

Objective: Although balance training has been used as an effective ankle injury rehabilitation program to restore neuromuscular deficits in patients with chronic ankle instability, it is not effectively used in terms of motor learning. Attentional focusing can be an effective method for improving ankle kinematics to prevent recurrent ankle injuries. This study aimed to 1) evaluate the effects of attentional focus, including internal and external focus, and 2) determine a more effective focusing method for patients with chronic ankle instability to learn balance tasks. Method: Twenty-four patients with chronic ankle instability were randomly assigned to three groups (external focus, internal focus, and no feedback) and underwent four weeks of progressive balance training. The three-dimensional ankle kinematics of each patient were measured before and after training as the main outcomes. Ensemble curve analysis, discrete point analysis, and post hoc pairwise comparisons were performed to identify interactions between groups and time. Results: The results showed that (1) the external focus group was more dorsiflexed and everted than the internal focus group; (2) the external focus group was more dorsiflexed than the no feedback group; and (3) the no feedback group was more dorsiflexed than the internal focus group. Conclusion: Because dorsiflexion and eversion are ankle motions that oppose the mechanism of lateral ankle sprain, using the external focus method during balance training may be more effective in modifying these motions, thereby reducing the risk of ankle sprain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.228-235
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• 2019

The purpose of this study was to investigate the effect of 6 weeks' accelerated rehabilitation with anti-gravity treadmill exercise on VAS, ROM, isokinetic myofunction, and dynamic stability after surgery of modified brostrom operation in chronic ankle instability patients. The subjects of this study were 12 chronic ankle instability patients who underwent modified Brostrom operation(MBO) by the same doctor. 6 weeks' accelerated rehabilitation program is scheduled to perform for 60min, everyday, and also anti-gravity program performed for 15~30min, everyday. The visual analog scale(VSA) and significantly decreased(p<.001) and ROM in all of dorsal flexion, plantar flexion, inversion and eversion significantly increased(p<.05) after 6 weeks' accelerated rehabilitation with anti-gravity treadmill exercise. Both inversion and eversion peak torque at $60^{\circ}/sec$(p<.001, p<.01) and at $180^{\circ}/sec$(p<.001) significantly increased after 6 weeks' accelerated rehabilitation with anti-gravity treadmill exercise respectively. In muscle defect, although inversion(p<.01) and eversion(p<.001) at $60^{\circ}/sec$ and inversion(p<.01) at $180^{\circ}/sec$ significantly decreased, eversion at $180^{\circ}/sec$ tended to decrease but did not change significantly after 6 weeks' accelerated rehabilitation with anti-gravity treadmill exercise. The dynamic stability significantly increased after 6 weeks' accelerated rehabilitation with anti-gravity treadmill exercise(p<.001). These results suggest that 6 weeks' accelerated rehabilitation with anti-gravity treadmill exercise has positive effect of VAS, ROM, isokinetic myofunction, and dynamic stability after surgery of modified brostrom operation in chronic ankle instability patients. Therefore, we consider that the accelerated rehabilitation with anti-gravity treadmill exercise, which is safely and fast method, has effect on more faster recovery of ankle stability, play ground and normal daily activities.

• Korean Journal of Applied Biomechanics
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• v.31 no.2
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• pp.113-118
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• 2021

Objective: The purpose of this study was to investigate differences of landing strategy between people with or without chronic ankle instability (CAI) during double-leg drop landing. Method: 34 male adults participated in this study (CAI = 16, Normal = 18). Participants performed double-leg drop landing task on a 30 cm height and 20 cm horizontal distance away from the force plate. Lower Extremities Kinetic and Kinematic data were obtained using 8 motion capture cameras and 2 force plates and loading rate was calculated. Independent samples t-test were used to identify differences between groups. Results: Compared with normal group, CAI group exhibits significantly less hip internal rotation angle (CAI = 1.52±8.12, Normal = 10.63±8.44, p = 0.003), greater knee valgus angle (CAI = -6.78±5.03, Normal = -12.38 ±6.78, p = 0.011), greater ankle eversion moment (CAI = 0.0001±0.02, Normal = -0.03±0.05, p = 0.043), greater loading Rate (CAI = 32.65±15.52, Normal = 18.43±10.87, p = 0.003) on their affected limb during maximum vertical Ground Reaction Force moment. Conclusion: Our results demonstrated that CAI group exhibits compensatory movement to avoid ankle inversion during double-leg drop landing compared with normal group. Further study about how changed kinetic and kinematic affect shock absorption ability and injury risk in participants with CAI is needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.37-44
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• 2016

The aim of the present study was to compare the strength, balance, and flexibility across two age groups (older adults vs. young adults). The isokinetic muscle function, ankle ROM, trunk forward flexibility, stability, and antropometric data for the elderly and 46 university students were collected. The results indicated that male older adults possessed relatively low flexibility (2.97cm) among the groups and showed better stability in the right foot than in the left foot and $35^{\circ}$ of plantar flexion ROM, which was not in the normal range. Their peak strength at the knee joint was below 50% of their counterpart. They revealed a hamstring deficit of 18.55%, ankle eversion deficit of 23.08%, and ankle inversion deficit of 19.19%. The results indicated that female older adults possessed comparable flexibility compared to female young adults. The reciprocal muscle strength ratio of both knees was under 50%, and the deficit was 14.32% (extension) and 19.73% (flexion). The ankle plantar flexion peak torque was approximately 62% (left) and 73% (right) of WS's. The ankle dorsi flexion deficit was 25.05% and the plantar flexion was 26.86%. The eversion deficit was 19.97% and the inversion was 21.09%. These results will be significant in establishing an elderly fitness enhancement program and policy.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.169-174
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• 2009

Purpose: To evaluate the clinical results between interlocking intramedullary nail with fibular fixation and nail only for treating distal tibiofibular diaphyseal fractures. Materials and Methods: From March 2003 to September 2006, 19 distal tibiofibular fractures were antegrade nailed after anatomical reduction and fixation of fibular fractures, and another 37 fractures fixed with nails only. Average age of patients was 48.6 years. These two groups were compared by VAS (visual analogue scale) & ankle ROM according to degree of comminution and fracture configuration. The statistical analysis was evaluated by t-test. Results: There was no statistical difference between fibular fixation group and non-fixation group in VAS score according to fracture comminution and configuration (p>0.05). However, compared according to fracture configuration, mean ankle eversion of fibular fixation group in oblique fractures was 18.3 degrees, and that of non-fixation group was 12.5 degrees (p<0.05). In addition, mean ankle plantar flexion, dorsiflexion, inversion and total ankle ROM of fibular fixation group in spiral fractures was 40.0, 20.0, 30.0 and 108.3 degrees of each and that of non-fixation group was 38.3, 18.5, 27.0 and 101.7 degrees (p<0.05). Conclusions: In oblique and spiral fractures of distal tibiofibular diaphysis, interlocking intramedullary nail with fibular fixation had the advantage in postoperative ankle ROM. So, it can be a worthy method for the treatment of distal tibiofibular diaphyseal fractures.

• Journal of Korean Foot and Ankle Society
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• v.16 no.1
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• pp.26-30
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• 2012

The subtalar joint is a complex joint that is functionally responsible for inversion and eversion of the hindfoot. Advances in optical technology and surgical instrumentation have allowed the arthorscocpic surgeon to investiagate the small joints including the subtalar joint. Indications for subtalar arthroscopy include pain, swelling, stiffness and locking. Therapeutic indications include treatment of chondromalacia, osteophytes, arthrofibrosis, synovitis, loose bodies, osteochondral lesions, excision of a painful os trigonum, arthrodesis, and FHL tendinopathy. Contraindications to subtalar arthroscopy include infection, advanced osteoarthritis with deformity, severe edema, poor vascularity and poor skin quality. Subtalar arthroscopy is a technically demanding and difficult procedure that should only be performed by experienced surgeons. With proper instrumentation and careful operative techniques, satisfactory results may be obtained with minimal morbidity.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.25-34
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• 2012

The purpose of this study was to determine the effects of landing height on the lower extremity during a counter movement jump. Fourteen healthy male subjects (age: $27.00{\pm}2.94$ yr, height: $179.07{\pm}5.03$ cm, weight: $78.79{\pm}6.70$ kg) participated in this study. Each subject randomly performed three single-leg jumps after s single-leg drop landing (counter movement jump) on a force platform from a 20 cm and 30 cm platform. Paired t-test (SPSS 18.0; SPSS Inc., Chicago, IL) was performed to determine the difference in kinematics and kinetics according to the height. All significance levels were set at p<.05. The results were as follows. First, ankle and knee joint angles in the sagittal plane increased in response to increasing landing height. Second, ankle and knee joint angles in the frontal plane increased in response to increasing landing height. Third, there were no significant differences in the moment of each segment in the sagittal plane for the jumping height increment. Fourth, ankle eversion moment and knee valgus moment decreased but hip abduction moment increased for the jumping height increment. Fifth, Ankle and knee joint powers increased. In percentage contribution, the ankle joint increased but the knee and hip joints decreased at a greater height. Lastly, as jumping height increased, the power generation at the ankle joint increased. Our findings indicate that the height increment affect on the landing mechanism the might augment loads at the ankle and knee joints.