• Korean Journal of Applied Biomechanics
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• v.28 no.2
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• pp.143-149
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• 2018

Objective: This study aimed to investigate the influence of landing foot orientations on biomechanics of knee joint in order to identify vulnerable positions to non-contact knee injuries during single-legged landing. Method: Seventeen men (age: $20.5{\pm}1.1 years$, height: $175.2{\pm}6.4cm$, weight: $68.8{\pm}5.8kg$) performed single-leg drop landings repeatedly with three different landing foot orientations. They were defined as toe-in (TI) $30^{\circ}$ adduction, neutral (N, neutral), and toe-out (TO) $30^{\circ}$ abduction positions. Results: The downward phase time of TI was significantly shorter than those of N and TO. The flexion and valgus angle of N was greater than those of TI and TO at the moment of foot contact. At the instance of maximum knee flexion, N showed the largest flexion angle, and TO position had the largest varus and external rotation angles. Regarding ground reaction force (GRF) at the moment of foot contact, TO showed the forward GRF, while others showed the backward GRF. TI indicated significantly larger mediolateral GRF than others. As for the maximum knee joint force and joint moment, the main effect of different foot positions was not significant. Conclusion: TI and TO might be vulnerable positions to knee injuries because both conditions might induce combined loadings to knee joint. TI had the highest mediolateral GRF with a shortest foot contact time, and TO had induced a large external rotation angle during downward phase and the peak forward GRF at the moment of foot contact. Conclusively, N is the preferred landing foot orientation to prevent non-contact knee injuries.

• Physical Therapy Korea
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• v.26 no.3
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• pp.23-31
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• 2019

Background: Measurement of passive ankle dorsiflexion range of motion (ADROM) is often part of a physical therapy assessment. Objects: The objective of this study was to identify the effects of subtalar joint neutral position (SJNP) on passive ADROM according to knee position in young adults. Methods: We recruited 14 young adult participants for this study. Two examiners used a universal goniometer to measure passive ADROM with and without SJNP. Dorsiflexion force was applied to the forefoot until maximum resistance was reached in two knee positions (extension and $90^{\circ}$ flexion) in the prone position. Subtalar joint position was also recorded at maximum ADROM. Passive ADROM was measured three times at different knee and subtalar joint positions, in random order. Two-way repeated-measures analysis of variance was used to compare the effects of subtalar joint and knee position on passive ADROM. Results: Passive ADROM was significantly lower with than without SJNP during both knee extension (mean difference: $7.4^{\circ}$) and $90^{\circ}$ flexion (mean difference: $16.9^{\circ}$) (p<.01). Passive ADROM was significantly higher during $90^{\circ}$ knee flexion than during knee extension both with (mean difference: $5.8^{\circ}$) and without SJNP (mean difference: $15.2^{\circ}$) (p<.01). The valgus position of the subtalar joint was significantly lower with than without SJNP during both knee extension (mean difference: $3.3^{\circ}$) and $90^{\circ}$ flexion (mean difference: $4.3^{\circ}$) (p<.01). Conclusion: Our results indicate that the gastrocnemius may limit ankle dorsiflexion more than the soleus does. Greater dorsiflexion at the subtalar and midtarsal joints was observed during passive ADROM measurement without than that with SJNP; therefore, SJNP should be maintained for accurate measurement of ADROM.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.391-395
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• 2011

To investigate the anticipatory effect on landing patterns during side-cutting maneuver, thirteen healthy female elite college soccer players participated in this study. Three-dimensional knee kinematics, effective mass and correlation between both these were measured and analyzed using a motion analysis and force plates. Each testing session included anticipated tasks, $45^{\circ}$ side-cutting tasks (AC), followed by a set of unexpected side-cutting (UC) in a random order. Knee flexion/extension, valgus/varus and internal/external rotation angles and effect mass were compared by using paired t-test. Also, correlation analysis was performed to identify the relationship between knee angles and effective mass. Effective mass during UC was greater than that during AC. Effective mass and maximum knee flexion angle were positively correlated during AC and not during UC. Based on the relationship between effective mass and knee flexion angle in AC, shock absorption can be controlled by knee joint flexion in pre-predicted movement condition. However, effective mass can not be controlled by knee flexion in UC condition. The unexpected load affects were more irregular on the knee joint, which may be one of the injury mechanisms of anterior cruciate ligament (ACL) in female soccer players.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.265-272
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• 2009

K. H. KIM, J. H. CHO, and S. C. LEE, The Effect of Taping on Lower Extremity during Jump Landing in Subjects with Functional Ankle Instability. Korean Journal of Sport Biomechanics, Vol. 19, No. 2, pp. 265-272, 2009. Ankle taping is thought that it can be very useful in clinical setting for reducing injury. However, the studies of ankle taping is focused only ankle joint. The purpose of this study was to examine the effect of taping on lower extremity during jump landing in subjects with functional ankle instability. we collected the data from VICON. Joint range of motion for sagittal plane, frontal plane and transverse plane were measured during a jump-landing task. Taping used in this study appeared to restrict ankle motion with altering the knee and hip joint ROM. We found ankle taping had effects of reducing PF, initial contact PF in sagittal plane, while increasing knee flexion, hip flexion, intial contact hip flexion statistically. It decreased ankle inversion, knee valgus, initial contact knee valgus, hip abduction in frontal plane and ankle abduction, hip internal rotation in transverse plane statistically. Ankle taping showed significant change Knee and hip joint ROM with ankle joint ROM.

• 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.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.805-814
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• 1997

Injuries to the menisci occur in a variety of ways, most commonly with a twist, pivot, squat, or valgus stress to the knee. Tear patterns are classified to longitudinal, horizontal, or transverse features according to the mechanism of injury. Work-related meniscal tear usually occurs with a repetitive usage of the foot, hence it can be classified as a cumulative traumatic disorder. We found a 47 year-old female worker who had been taking charge of repetitive foot-switch stepping for 8 years. She suffered from pain in the right knee since 5 months ago. Tenderness along the medial joint line of the right knee was observed and pain was aggravated with full flexion of the right knee. On magnetic resonance imaging, high signal intensity was observed at the posterior horn of the medial meniscus of the right knee. Degenerative longitudinal and transverse complex tear in the medial meniscus was observed on arthroscopy. Arthroscopic partial meniscectomy was performed. We surveyed the work process and the health status of co-workers. It turned out that the work process was compatible to injure the meniscus and nine out of fourteen co-worker(64.3%) complained pain of the knee. No other factors related to her meniscal tear could be found except for the situation at her work. Therefore, we conclude that meniscal tear is related to the repetitive stepping of foot switch.

• Journal of Korean Orthopaedic Sports Medicine
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• v.4 no.2
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• pp.74-78
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• 2005

Even though, anterior knee pains are most frequently encountered in knee clinics, many physicians use a 'recipe'-type of approach to their treatment. But many predisposing factors have been included internal rotation of the femur, valgus knee alignment, external rotation of the extensor mechanism, patellar alta, a flat trochlear groove, patella with poor congruence and ligatmentous laxity. Many scientific principles on which these commonly used treatment are based, can lead to refinements and improvement in treatment. We reviewed and summarized the recent functional anatomical and biomechanical data that are most relevant to the contemporary treatment of patellofemoral joint disorders.

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.175-182
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• 2010

The purpose of this study was to evaluate the biomechanical effect of sports taping on the lower limb during drop landing. Twelve male university students who have no musculoskeletal disorder were recruited as the subjects. Principal strain, median frequency, vertical GRF, loading rate, angular velocity and resultant joint moment were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between taped and untaped conditions(p<.05). The results showed that principal strain of the thigh and the shank in taping group were significantly less than those found in control group. These indicated that sports taping may prevent excessive mechanical strain caused by impact force during the deceleration phase. Flexion(-)-extension(+) and varus(-)-valgus(+) resultant joint moment of the knee joint in taping group were greater than corresponding value for control group. It seems that extensor muscle of the knee joint were not only supported by sports taping during knee flexion but also sports taping is effective for minimizing the possibility of injury.

• Knee surgery & related research
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• v.30 no.4
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• pp.293-302
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• 2018

Purpose: High tibial valgus osteotomy (HTO) is a well-established surgical procedure for patients with medial compartment osteoarthritis (OA) of the knee. The hybrid closed-wedge HTO (CWHTO) procedure permits extensive correction in patients with severe deformities or patellofemoral joint OA. The aim of this study was to report the short-term results in a consecutive series of patients treated with hybrid CWHTO. Materials and Methods: We retrospectively evaluated the clinical outcomes and radiographic parameters in 29 consecutive knees that underwent hybrid CWTHO to correct medial compartment OA at an average follow-up of 52.6 months. Clinical outcomes were assessed using the Lysholm score and knee scoring system of the Japanese Orthopedic Association (JOA). The Kellgren-Lawrence grading system and pre- and postoperative mechanical axis (MA), femorotibial angle (FTA), posterior tibial slope, and patella height were assessed. Results: The FTA and MA significantly changed from $180.7^{\circ}$ to $170.4^{\circ}$ and from $22.0^{\circ}$ to $60.2^{\circ}$, respectively. No significant differences were observed between the mean pre- and postoperative posterior tibial slope, Insall-Salvati ratio, or Caton-Deschamps index. The postoperative JOA and Lysholm scores significantly improved from 76.7 to 95.8 and from 58.8 to 90.2, respectively. Conclusions: Satisfactory outcomes can be achieved with hybrid CWHTO in patients with medial OA.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.183-190
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• 2015

Objective : Walking with a Material handling is an activity frequently undertaken by agricultural workers in Korea, due to the nature of their work. This study aimed to investigate differences in biomechanical variables according to the mechanical alignment of the lower limbs when walking with a heavy load, and to use this as basic data in the design of various working environments to reduce the skeletomuscular burden on the knee joint. Method : The study subjects comprised of 22 right-foot dominant adult men and women aged between 20 and 23 years. The subjects were divided into a varus or valgus group according to the mechanical alignment of the lower limb by using radiographic findings. The subjects walked without any load and with a load of 10%, 20%, or 30% of their body weight held in front of them. The Kwon3d XP program was used to calculate biomechanical variables. Results : The flexion/extension moment of the knee joint showed a decreasing trend with increased load, irrespective of the mechanical alignment of the lower limb, while the varus group did not show normal compensatory action when supported by one leg at the point of maximum vertical ground reaction force. In addition, in terms of the time taken, subjects showed no difficulties in one-foot support time up to 20%/BW, but at 30%/BW, despite individual differences, there was an increase in single limb. The increased load resulted in a decrease in the ratio of standing phase to ensure physical stability. The valgus group showed a trend of increasing the stability of their center of mass with increasing load, through higher braking power in the early standing phase. Conclusion : In conclusion, although there was no statistical difference in biomechanical variables according to the mechanical alignment of the lower limbs, the varus group showed a more irregular walking pattern with a Material handling than the valgus group, partially proving the association between lower limb alignment and walking with a Material handling.