• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.49-63
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• 2003

For this study, four male university Taekwondo players were randomly chosen, between the weight categories of 60Kg and 80Kg. Their side kicks (yeop chagi), which are part of foot techniques, were kinematically analyzed in terms of the time, angle, and angular velocity factors involved with the kicks through the three-dimensional imaging. The results of the analysis are as fellows. 1. Time factor The first phase(preparation) was 0.48sec on average, accounting for 60% of the entire time spent; the second phase(the minimum angle of the knee joint) was 0.21sec on average, taking up 26% of the whole time spent; and the third phase(hitting) was 0.11sec on average, representing 14% of the entire time spent. 2. Angle factor In the first phase(preparation), rotating their bodies along the long axis, the players bended their hip and knee joints a lot, by moving fast in the vertical and horizontal directions, in the second phase(the minimum angle of the knee joint), the players continued to extend their bodies along the vertical axis, while pronating their lower legs and bending their hip and knee joints a lot to reduce the radius of gyration, and in the third phase(hitting), they extended their knee joints greatly so that the angle movements of their lower bodies shifted to circle movements. 3. Angular velocity factor In the first phase(preparation), the angular velocity of the hip and knee joints increased. while moving horizontally and rotating the body along the long axis; in the second phase(the minimum angle of the knee joint), the angular velocity increased by bending the hip and knee joints fast to reduce the rotation radios; and in the third phase(hitting), the angular velocity was found to have increased, by rotating the body along the long axis to increase the angular velocity and shifting the angular momentum of the pronated knee joint to the circular momentum.

• The Journal of Korean Physical Therapy
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• v.32 no.1
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• pp.52-57
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• 2020

Purpose: This study compared the muscle activities of the Vastus medialis oblique (VMO) and the Vastus lateralis (VL) at three different knee extension angles: 90°, 135°, and 180° in the sitting position. Methods: Twenty subjects between 20 and 30 years of age participated in the study. A mobile phone application called the Clinometer was used to measure the knee joint angle. Electromyography (EMG) was performed to measure the muscle activities of the VMO and VL muscles during knee isometric extension exercises. The pulling sensor was used to maintain 70% of the maximum strength of the knee extensor continuously in the sitting position. After attaching the EMG sensor, the subjects were asked to perform isometric knee extension exercises randomly among three knee extension angles (90°, 135°, or 180°) in the sitting position. One-way repeated measures analysis of the variance and a Bonferroni post hoc test was used to identify the VMO and VL muscle activity during knee extension angles among 90°, 135°, and 180°. Results: The VMO and VL muscle activities increased with increasing knee extension angle in the sitting position (p<0.01). Conclusions: Knee extension exercise at a 180° angle in the sitting position can be recommended to increase the muscle activity of the VMO and VL muscle activities efficiently.

• The Journal of Korean Physical Therapy
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• v.33 no.3
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• pp.162-167
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• 2021

Purpose: A hyperextended knee is described as knee pain associated with an impaired knee extensor mechanism. Additionally, a hyperextended knee may involve reduced position sense of the knee joint that decreases the individual's ability to control end-range knee extension movement. The purpose of this study was to investigate the effects of visual biofeedback information for plantar pressure distribution on knee joint angle and lower extremity muscle activities in participants with hyperextended knees. Methods: Twenty-three participants with hyperextended knees were recruited for the study. Surface electromyography signals were recorded for the biceps femoris, rectus femoris, gastrocnemius, and tibialis anterior muscle activities. The plantar pressure distribution was displayed and measured using a pressure distribution measuring plate. Knee joint angle kinematic parameters were recorded using a motion analysis system. The visual biofeedback condition was the point at which the difference between the forefoot and backfoot plantar foot pressure on the monitor was minimized. The Wilcoxon signed-rank test was used to determine the significance between the visual biofeedback condition and the preferred condition. Results: The knee joint angle was significantly decreased in the visual biofeedback condition compared to that in the preferred condition (p<0.05). The rectus femoris and gastrocnemius muscle activities were significantly different between the visual biofeedback and preferred conditions (p<0.05). Conclusion: The results of this study showed that visual biofeedback of information about plantar pressure distribution is effective for correcting hyperextended knees.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.2
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• pp.1-10
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• 2006

The purpose are to assess the efficacy of a contact lateral-wedged insole with strapping on the femorotibial angle in patients with varus deformity osteoarthritis of the knee after treatment period. 25 outpatients with knee osteoarthritis (OA) were randomized to be treated with a contact lateral-wedge insole with strapping. Standing radiographs were used to analyze the femorotibial angle for each subject. The result of repeated two-way ANOVA's reveled that a contact lateral-wedged insole with strapping produced significantly differences in the femorotibial angle between groups after treatment period (P<0.05). and repeated one-way ANOVA's reveled that it produced significantly differences in the femorotibial angle between experimental groups after treatment period (P<0.05). We suggest that these results may be beneficial for manufacturing foot orthotic devices, such as wedged insoles, to control medial and later compartment forces in the knee varus-valgus deformity.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.1
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• pp.36-43
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• 2007

Purpose: An objective analysis and observations were to be done on hemiplegia patients that are wearing a walking support device, Stroke shoes. Their improvements in walking pace, the reduction of distance between the two knee joint, the increase of curve angle of the knee joint and their steps and the reduction of ankle joint upon swing phase were analyzed using a 20 walking analyzer. Methods: An examination was carried out to see the patients' communication skill and independent walking and then let them walk with the Stroke shoes on to get results before and after wearing it. Simi Reality Motion Systems GmbH (Germany, 2007) was used to analyze the results regarding knee joint and ankle joint angle changes of sagitta plane and coronal plane, stepping distances, distances between the knees and walking pace. Results: 1. The articulation angle of ankle joint during swing phase decreased and knee joint has shown a statistically significant increase in such value(p<0.05). 2. Only knee joint showed a significant increase in articulation angle during heel strike(p<0.05). 3. Knee joint showed a significant increase in articulation angle during toe off(p<0.05). 4. The distance between the two knees as well as their foot steps significantly decreased compared with when Stroke shoes were not worn(p<0.05). 5. Stroke shoes with FES have shown positive effects on the patients in improving their walking styles overall. (p<0.05). Conclusion: There was an improvement in rotation walking pattern by a reduction in the distance between the knees after wearing Stroke shoes with FES. Plantar flexion reduced that occurred in ankle joint during walking and flexion angle increased in knee joint, both of which improved foot drop which was a major problem in hemiplegia patients. Also it is believed that the device will have some positive influences on knee joint stiffening paralysis to aid in improving inefficient walking phases.

• Journal of Korean Medicine Rehabilitation
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• v.24 no.4
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• pp.163-176
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• 2014

Objectives To investigate the relationship of forward head posture to heart rate variability and standing posture (pelvic tilt, knee flexion, calcaneal eversion). Methods In the present study, thirty two subjects were recruited by convenience sampling. The forward head posture was measured via the craniovertebral (CV) angle. The pelvic tilt angle, the knee flexion angle, the calcaneal eversion angle, and the heart rate variability were measured. The correlations of forward head posture to heart rate variability and standing posture (pelvic tilt, knee flexion, calcaneal eversion) were analyzed. Results In the present results, there was a significant negative correlation between X-ray CV angle and other regions except the headache. There was a weak positive correlation between Posture CV angle and SDNN. Significant positive correlation was found between KFA and difference between Lt. & Rt. CEA. Significant weak negative correlation was found between SDNN and difference between Lt. & Rt. CEA. Conclusions Biomechanical associated with physical pain and heart rate variability, and it is related to the forward head posture changes and also suggest that clinical care is needed for this.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.327-340
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• 2003

The purpose of this study was to investigate the height of jump, angle of the ankle and knee, the angular velocity of the ankle and knee between two types of ballet shoes during a jump in the 1st position. The subjects were 5 female ballet majors of university in Busan the majors who have been dancing ballet for six years on the average. The conclusions are as follows: 1. The height of jump had no significant difference between two types of ballet shoes, and then the average of the height of jump with point shoes group ($20.24{\pm}4.62\;cm$) was a little higher than ballet shoes group ($17.50{\pm}4.05\;cm$). 2. The angle of the ankle had no significant difference for all events between two types of ballet shoes. The minimum angle of ankle joint was represented to $54.36_{\circ}$ at the E1 of the left ankle angle of the ballet shoes and the maximum value was showed $155.43_{\circ}$ at the E3 of the right ankle angle of the point shoes. 3. The angle of the knee had no significant difference for all events between two types of ballet shoes. The minimum angle of knee joint was represented to $99.54_{\circ}$ at the E1 of the left knee angle of the ballet shoes and the maximum value was showed $174.25_{\circ}$ at the E3 of the right knee angle of the point shoes. 4. The ankle velocity of the ankle had no significant difference for all events between two types of ballet shoes. The minimum angular velocity of the ankle was represented to 4.35 deg/s at the maximum height(E3) of the point shoes and the maximum value was showed 597.81 deg/s at the take-off(E2) of the right ankle angle of the point shoes. 5. The angular velocity of the knee had significant difference between two types of ballet shoes at the event 1(p<.05). The minimum angular velocity of the hee was represented to -1.68 deg/s at the maximum height(E3) of the point shoes and the maximum value was showed 360.25 deg/s at the take-off(E2) of the left knee angle of the ballet shoes. The other events had no significant difference between two types of ballet shoes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1445-1446
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• 2011

• Journal of Korean Physical Therapy Science
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• v.1 no.2
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• pp.289-299
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• 1994

This study was researched the general characteristics, the elbow-knee joint form, the varus and valgus angle and the both knee joint distance of the 215 persons form July 1, 1994 to July 15, 1994. The results were as follows : 1. The form of elbow joint was significant statistically in the sex group(p<0.05). 2. The angle of elbow joint was very significant statistically in the age group and sex. B.M.I. group(p<0.001, p<0.01, p<0.01), and the average angle was $9^{\circ}.51{\pm}4^{\circ}.79$(n=215). 3. The angle of Cubitus valgus was very significant statistically in the age group(p<0.001), and the average angle of Cubitus valgus was $10^{\circ}.85{\pm}3^{\circ}.76$(n=187). 4. The angle of Knee joint was significant statistically in the age group(p<0.05), and the its average angle was $7^{\circ}.63{\pm}4^{\circ}.52$(n=215). 5. The angle of Genu varus was significant statistically in the age and sex group(p<0.05, p<0.05), and the its average was $6^{\circ}.92{\pm}2^{\circ}.36$(n=27). 6. The angle of Genu valgus was very significant statistically in the age group(p<0.001), and the its average angle was $9^{\circ}.75{\pm}2^{\circ}.94$(n=149). 7. The distance of both Knee joint was significant statistically in the age group and B. M. I. group (p<0.001, p<0.05), and the its average distance was $2.55{\pm}1.45cm$(n=135).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.24-24
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• 2003

For the elderly, achieving a close-to-normal ambulation is important for activities of daily life. Recent researches of SE(Silver Engineering) restoring physical ability would help the elderly by developing the advanced gait assisting devices and orthoses. For the applications using the advanced technologies, the gait characteristics of the elderly must be understood. However, a few studies were performed to investigate the physiological or pathological gaits. The purpose of this study is to provide the gait analysis data and also to investigate relationships between alignment of the lower limb, foot progression angle and knee joint moments in the healthy elderly. By participating a total of 20 healthy elderly persons in this study, the following facts were found: 1) Cadence showed 114.8 steps/min, gait speed showed 1.05 m/s, time per a stride showed 1.06 sec, time per a step showed 0.53 sec, single-supporting phase was 0.41 sec, double-supporting phase was 0.24 sec, stride length was 1.04m, Step length was 0.56m; 2) The maximum knee flexion angle through swing phase showed left 46.82$^{\circ}$, right 40.19$^{\circ}$ and the maximum knee extension angle showed left -1.32$^{\circ}$, right 2.01$^{\circ}$. Knee varus showed left 26.90$^{\circ}$, right 30.93$^{\circ}$; 3) The maximum knee flexion moment showed left 0.363 Nm/kg, right 0.464 Nm/kg, The maximum knee extension moment showed left 0.389 Nm/kg, right 0.463 Nm/kg. The maximum knee adduction moment showed left 0.332 Nm/kg, right 0.379 Nm/kg. The maximum internal rotational moment showed left 0.13 Nm/kg, right 0.140 Nm/kg; 4) The subjects who had varus alignment of the lower extremity had statistically higher in knee adduction moment in mid stance phase; and 5) The subjects who had large foot progression angle had statistically lower in knee adduction moment in late stance phase.