• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.11 no.4
• /
• pp.323-330
• /
• 2017

Knee sleeve has been used for prevention of sport injuries as well as rehabilitation. To investigate prevention of sport injuries of knee sleeve, it is important to evaluate balance associated with proprioception. The aim of this study was to evaluate the effects of a knee sleeve with a pad that stimulate to golgi tendon organ (GTO_PAD) on proprioception and balance ability. Five healthy males were participated for the study. They were asked to reenact target angle with Biodex and perform one leg standing with knee sleeve and knee sleeve with GTO_PAD. There was no significant difference in %Target angle, but the value of %Target angle was higher in subjects wearing knee sleeve with GTO_PAD than only knee sleeve, except for one subject. During one leg standing, time duration was increased in subjects wearing knee sleeve with GTO_PAD. The length of center of pressure in x-axis (COPx) and COP in y-axis (COPy) were decreased when wearing knee sleeve with GTO_PAD (COPx : $162.06{\pm}58.99mm$ in knee sleeve vs. $149.03{\pm}45.30mm$ in knee sleeve with GTO_PAD, COPy : $310.79{\pm}115.89mm$ in knee sleeve, $291.57{\pm}76.53mm$ in knee sleeve with GTO_PAD). There was significant differences in INI_transition, steady, and LAT_transition phase (all, p < 0.05). These findings support that wearing knee sleeve with GTO_PAD might enhance proprioception and balance.

• Journal of Korean Physical Therapy Science
• /
• v.25 no.2
• /
• pp.7-14
• /
• 2018

Purpose: This study was conducted to analyze the effect of bag type on gait kinematic factors. The purpose of this study was to compare the Cobb's angle, leg angle and foot pressure difference according to bag type among 20 university students. Methods: The bag type was applied with two kinds of bags: not wearing a bag, backpack, and an eco bag. The bag weight was 10% of subjects weight in during experiment and only bag weight was 0.5kg. Results: Knee joint angle is increased when wearing backpack or an eco bag than not wearing bag. Cobb's angle increased when wearing backpack and wearing eco back. The difference in right and left foot pressure increased when wearing eco bag than not wearing bag and wearing backpack. Conclusion: Therefore, wearing a heavy backpack or an eco bag when walking for a long time may cause scoliosis and change the walking form.

• Korean Journal of Applied Biomechanics
• /
• v.21 no.3
• /
• pp.335-343
• /
• 2011

Patellofemoral pain syndrome is the most common problem involving the knee, accounting for 25% of knee injuries. Repetitive, overuse activities cause increased force at the patellofemoral joint, resulting in pain during flexion and extension activities. Most research have been conducted in exploring the patellofemoral compressive force in gait, squat and lunges, even though in real cases, possibilities in landing exist. The purpose of this study was to compare the differences in patellofemoral compressive force according to two different height. Sixteen collegiate male students(age: 22.25 ${\pm}$ 3.30 yrs, height: 177.25 ${\pm}$ 4.44 cm, weight: 77.50 ${\pm}$ 8.18 kg) were chosen. The subjects performed drop landings in 45 cm, 60 cm. The findings demonstrated that higher height showed peak knee extension moment, quadriceps contraction force, patellofemoral compressive force with increased VGRF. Regarding the patellofemoral joint compressive force, it increased by quadriceps contraction force with knee flexion during landing, yet, it showed no difference in maximal knee flexion. To minimize patellofemoral joint stress and reduce the likelihood of developing PFPS, we recommend that predesigned quadriceps and hip muscle group strengthening are needed during conditioning and training.

• Journal of the Ergonomics Society of Korea
• /
• v.30 no.2
• /
• pp.357-363
• /
• 2011

Objective: The aim of this study is to set the design direction of the lift chair's tilting seat for development. Background: Great attention has been shown to the development of senior friendly product, because of increasing elderly population rapidly in Korea. Therefore, we need to study on sit-to-stand(STS) motion of elderly systematically for developing lift chair that is one of senior friendly products. Method: In this study, we analyzed joint moment(knee, hip) and muscle activity (Erector spinae, Rectus femoris, Vastus lateralis) on STS motion of elderly(female, 60~70: 7) and young people(female, 20~30: 7) using 3 dimension motion capture camera, force plate, wireless EMG. Results: The results of muscle activity showed a similar trend but the results of joint moment were a lot of differences between the young and the elderly. Conclusion: The results of knee joint moment suggest the angle(10~30deg)-adjustable seat that can be better than to find the optimal seat's angle. Application: The method and results of this study are expected to develop senior friendly product and verification as well as be available to various application.

• Korean Journal of Applied Biomechanics
• /
• v.28 no.3
• /
• pp.159-164
• /
• 2018

Objective: The aims of this study were to determine the impact peak force and kinematic variables in running speed and investigate the relationship between them. Method: Thirty-nine male heel strike runners ($mean\;age=21.7{\pm}1.6y$, $mean\;mass=72.5{\pm}8.7kg$, $mean\;height=176.6{\pm}6.1cm$) were recruited in this investigation. The impact peak forces during treadmill running were assessed, and the kinematic variables were computed using three-dimensional data collected using eight infrared cameras (Oqus 300, Qualisys, Sweden). One-way analysis of variance ANOVAwas used to investigate the influence of the running speed on the parameters, and Pearson's partial correlation was used to investigate the relationship between the impact peak force and kinematic variables. Results: The running speed affected the impact peak force, stride length, stride frequency, and kinematic variables during the stride phase and the foot angle at heel contact; however, it did not affect the ankle and knee joint angles in the sagittal plane at heel contact. No significant correlation was noted between the impact peak force and kinematic variables in constantrunning speed. Conclusion: Increasing ankle and knee joint angles at heel contact may not be related to the mechanism behind reducing the impact peak force during treadmill running at constant speed.

• Korean Journal of Applied Biomechanics
• /
• v.14 no.3
• /
• pp.17-35
• /
• 2004

The purpose of this study is to explain developmental process of gait via angle-angle diagram to understand how coordinated relationships and control change with age. Twenty four female children, from one to five years of age were the test subjects for this study, and their results were compared to a control group consisting of twenty one adult females. The Vicon 370 CCD camera, VCR, video timer, monitor, and audio visual mixer was utilized to graph the gait cycle for all test subjects. Both coordinated Intra-limb relationships, and range of motion and timing according to quadrant were explained through the angle angle diagram. Movement in the sagittal plane showed both coordinated relationships and control earlier than movement in the coronal or transverse plane. In the sagittal plane, hip and Knee coordinated relationships developed first (from one year of age.) Coordinated relationships in the Knee and ankle and hip and ankle developed next, respectively. Both hip and ankle and knee and ankle development were inhibited by the inability of children to completely perform plantar flexion during the swing and initial double limb support phases. Children appeared to compensate for this by extending at their hip joint more than adults during the third phase, final double limb support. In many cases the angle angle diagram for children had a similar shape as adult's angle angle diagram. This shows that children can coordinate their movements at an early age. However, the magnitudes and timing of children's angle angle diagrams still varied greatly from adults, even at five years of age. This indicates that even at this age, children still do not possess full control of their movements.

• Physical Therapy Korea
• /
• v.25 no.3
• /
• pp.19-26
• /
• 2018

Background: Genu varum is also known as bow leg. It is a deformity wherein there is lateral bowing of the legs at the knee. it does give rise to pain, and persistent bowing can often give rise to discomfort in knees, hips and ankles. Objects: This study investigated the effect of narrow squats on the knee joint during a gait and distance between the knees of person with genu varum. Methods: This study analyzed 23 patient with genu varum that grade III, 12 narrow squat group and 11 genenal squat group in motion analysis laboratory. The subjects of experiment took gait before and after intervention, the range of joint motion, moment of knee joint adduction, power, distance of the knees were measured. And in order to make an analysis between groups, an paiered t-test and independent t-test was carried out. For statistical significance testing, it was decided that significance level ${\alpha}$ be .05. Results: It was shown that the group of narrow squat exercise significantly decreased in distance of knees (p<.05),In moment of adduction of knee joint, it was shown to significantly decrease in two groups (p<.05), was significantly decreased in adduction, abduction, and rotation (p<.05). In relation of peak-knee adduction moment and valgus angle, there was significant decrease in narrow squat group (p<.05). Conclusion: When the above result of study were examined, a narrow squat exercise given to the genu varum patients significantly decreased the distance between the knees, range of knee adduction and abduction, knee adduction moment, knee power. And stability gains through the decrease of excursion of knee medial part be effective for the correction of genu varum deformation.

• Journal of the Korean Society of Physical Medicine
• /
• v.14 no.3
• /
• pp.21-27
• /
• 2019

PURPOSE: This study examined the changes in the kinematic variables during walking on a downhill ramp according to the shoe heel height. METHODS: The subjects were 10 adult women with no history of musculoskeletal disorders who agreed to participate in the study. Data were collected using a motion analysis system (VICON) consisting of six infrared cameras. The slope was 120 cm in width, 200 cm in length, and 15 in inclination. To confirm the change in gait parameters (stride length, gait speed) and lower extremity joint angle according to the heel heights of the shoes, flat, 5 cm, and 10 cm heel shoes were prepared and walked alternately. RESULTS: As a result, both the stride length and walking speed showed significant differences according to the heel height between flat and 10 cm (p<.05). In the sagittal plane, there was no significant difference in the hip joint and knee joint, but a significant difference was observed in all events in the ankle joint on all heel heights (p<.05). In particular, the heel strike and mid stance events showed significant differences among all height conditions (p<.05). No significant difference was observed in any of the joint angle changes in the frontal plane (p>.05). CONCLUSION: As the shoe heel height increased, the instability increased and efforts to secure the stability were made, leading to a shortened stride length, walking speed, and angle of the ankle joint.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.4
• /
• pp.445-453
• /
• 2014

The purpose of this study was to analyze the gait characteristics and interaction between lower extremity joints according to shoe's heel heights in young women. Participants were selected as subject consisted of young and healthy women (age: $23.71{\pm}1.49yrs$, height: $165.92{\pm}2.00cm$, body weight: $54.37{\pm}3.46kg$) and walked with 3 types of shoe's high-heel (0, 5, 9 cm). The variables analyzed consisted of the displacement of Y axis in center of mass ([COM]; (position, velocity), front rear(FR) and left right(LR) angle of trunk, lower extremity joint angle (hip, knee, ankle) and asymmetric index (AI%). The displacement of Y axis in COM position showed the greater movement according to increase of shoe's heel heights, but velocity of COM showed the decrease according to increase of shoe's heel heights during gait. The hip and knee angle didn't show significant difference statistically according to increase of shoe's heel height, but left hip and knee showed more extended posture than those of right hip and knee angle. Also ankle angle didn't show significant difference statistically, but 9 cm heel showed more plantarflexion than those of 5 cm and 0 cm. The asymmetric index (AI%) showed more asymmetric 9 cm heel than those of 0 cm and 5 cm. The FR and LR angle in trunk tilting didn't show significant difference statistically according to the increase of shoe's heel height during gait in young women.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.1
• /
• pp.1-10
• /
• 2008

This study analyzed the rear foot angle of the supporting leg and the anatomical rotation angle of the kicking angle in soccer instep kick and drew conclusions as follows. When the supporting leg was landing on the ground, the valgus angle of the ankle joint reached the maximum peak, and plantar flexion was slightly different in the timing of the maximum peak between the two groups. The flexion angle of the rear foot was statistically significantly different between the two groups, and the movement of the crus on the landing of the supporting foot did not show a statistically significant difference between the groups. The crus leaned backward most before the impact, and the side to side gradient of the crus on impact was $22^{\circ}$. The flexion/extension of the hip joint of the kicking leg reached the maximum peak when the supporting foot was landing on the ground, and at the moment, the maximum extension angle of the hip joint was over $30^{\circ}$. The flexion angle of the knee joint of the kicking leg was largest after landing. While the maximum plantar flexion angle and maximum valgus angle of the ankle joint were not significantly different between the two groups, the maximum external rotation angle was significantly different.