• PNF and Movement
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• v.16 no.2
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• pp.267-273
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• 2018

Purpose: Leg length discrepancy (LLD) is one of the risk factors for postural imbalance. This study aimed to investigate the effect of induced leg length discrepancy on the limitation of stability (LOS) and static postural balance. Methods: Thirteen adults (males, 7; females 6) participated in this study. The LOS and static postural balance [sway length, sway area, and sway velocity of center of gravity (COG) displacement] were measured by the balance trainer system. The subjects were asked to move the COG for the anterior, posterior, and left and right directions maximally and to keep standing on the platform with and without induced LLD for 30 s in the open and closed eyes conditions, respectively. The LLD was artificially induced to 2 cm using insole. Wilcoxon test was used to compare the LOS and the static postural balance between with and without induced LLD. Results: The anterior and posterior LOS significantly decreased in induced LLD (p<0.05), and the left and right LOS were not significantly different between with and without LLD (p>0.05). Sway length, sway area, and sway velocity of the COG displacement significantly decreased in induced LLD (p<0.05). Conclusion: This study suggests that induced LLD could decease the antero-posterior LOS and increased the static postural balance. Therefore, the LLD could disturb the postural balance.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.26 no.1
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• pp.73-78
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• 2020

Background: The leg length discrepancy (LLD) have been implicated with degenerative diseases since the early 1970s, which also causes musculoskeletal asymmetry problems. The LLD appears due to factors such as balance ability, response time, and muscle strength between the shorter and longer leg. In this study, the effect of manual therapy to LLD has been studied. Methods: Manual therapy has been applied on shorter leg of 30 patients with LLD. The manual therapy was conducted for 2~3 minutes 3 times a week for 4 weeks. Results: The leg length of shorter leg were measured at initial baseline and after 4 weeks. the average leg length of shorter leg increased from 94.10 cm to 94.33 cm. Conclusion: This paper reports that the manual therapy has positive effects on LLD. It was studied by conducting manual therapy on muscles and joints related to shorter leg. In the future, the muscles and joints of the longer leg should be considered and various age group should be studied to develop the understanding of the effect of manual therapy on LLD.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.101-113
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• 2016

Objective: The purpose of this study was to investigate the effect of leg length discrepancy (LLD) on the human body during gait and standing posture. Methods: The study group comprised of 17 adult participants with LLDs of <1 cm. LLDs were artificially induced to 0, 1, 2, and 3 cm. The proportion of weight distribution, shift of the mean center of pressure, and Cobb's angle were measured in the standing position. Kinematic variables such as walking and striding width and time, and the proportion of stance phase for single- and double-limb gait were measured as well. The participants were required to either stand or walk on a treadmill (Zebris FDM) with a pressure plate, and the Cobb's angle measurements were obtained from radiographs. Results: A discrepancy of 3 cm in leg length resulted in a statistically significant shift of the center of pressure in the standing position. Moreover, the Cobb angle increased as the discrepancy became larger. The step length and width of the longer (left) leg during gait statistically significantly increased when the discrepancy was 2 cm. In addition, step time was statistically significant when the discrepancy between the longer (right) and shorter (left) legs was more than 2 cm. The proportion of single-limb stance phase was statistically significant as the discrepancy became larger, especially when the discrepancy was >2 cm for the longer (right) leg and 1 cm for the shorter (right) leg. Conclusion: The study showed that LLD influenced deformations of the human body and walking.

• PNF and Movement
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• v.20 no.1
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• pp.59-66
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• 2022

Purpose: The aim of this research was to verify the relationship between three-dimensional (3D) ground reaction force (GRF) and severity of leg length discrepancy (LLD) while walking at a normal speed. It used a 3D motion analysis system with force platforms in standing workers with LLD. Methods: Subjects comprising 45 standing workers with LLD were selected. Two force platforms were used to acquire 3D GRF data based on a motion analysis system during gait. Vicon Nexus and Visual3D v6 Professional software were used to analyze kinetic GRF data. The subjects were asked to walk on a walkway with 40 infrared reflective markers attached to their lower extremities to collect 3D GRF data. Results: The results indicated the maximal force in the posterior and lateral direction of the long limb occurring in the early stance phase during gait had significant positive correlation with LLD severity (r = 0.664~0.738, p <0.01). In addition, the maximal force medial direction of the long limb occurring in the late stance phase showed a highly positive correlation with the LLD measurement (r = 0.527, p <0.01). Conclusion: Our results indicate that greater measured LLD severity results in more plantar pressure occurring in the foot area during heel contact to loading response of the stance phase and the stance push-off period during gait.

• The Journal of Korean Physical Therapy
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• v.31 no.6
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• pp.368-371
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• 2019

Purpose: The purpose of this study was to investigate the effects of leg length discrepancy on kinematic changes of the pelvis and hip during gait. Methods: A total of ten healthy women with no history of neurological, musculoskeletal surgery or injuries, or pain in the lower limbs were recruited. They were assigned to two groups; the experimental group (LLD) consisting of five subjects leg length discrepancy of 10mm to 18mm and the control group (CON) consisting of five subjects leg length discrepancy of<10 mm. All participants were instructed to perform three walking trials for further analysis by using the Cortex 3.0 software program. Independent T-test and Mann-Whitney test were used to examine the effects of mild LLD on kinematic changes of the pelvis and hip during gait. Results: Angles of hip flexion, hip abduction, pelvic obliquity, and pelvic tilt in the experimental group were not significantly different compared to those of the control group. Conclusion: Mild leg length discrepancy induces kinematic changes in the lower limbs, including decreased hip flexion, increased hip abduction, and increased pelvic obliquity in the shorter limb, and increased hip adduction and increased pelvic obliquity in the longer limb. However, those changes were not significant.

• The Journal of the Korean bone and joint tumor society
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• v.17 no.1
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• pp.1-10
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• 2011

The main goals of treatment of malignant bone tumor are the prolongation of life survival and the improvement of quality of life. In growing children, however, leg length discrepancy (LLD) is one of major problem in the treatment of malignant bone tumors. Therefore, the precise understanding of growth in children is essential, and the prediction of LLD is critical in deciding the time and options of surgery. In addition, to use the adequate method of growth expectation, periodic follow-up and collaboration with patient's parents are needed.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.59-67
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• 2019

Purpose : The purpose of this study was to analyze the dynamic range of motion (ROM) of pelvic and translation of center of mass (COM) when wearing different shoe insole lifts according to leg length discrepancy (LLD) during free speed gait. Methods : Thirty-five healthy adults were participated in this study. Kinematic data were collected using a Vicon motion capture system. Reflective and cluster 40 markers attached to participants lower extremities and were asked to walk in a 6 m gait way under three different shoe lift conditions (without any insole, 1 cm insole, and 2 cm insole). The pelvic ROM and COM translation in three planes were sorted using a Nexus software, and a Visual3D motion analysis software was used to coordinate all kinematic data. Results : There were significantly increased maximal pelvic elevation and total pelvic range in coronal plane when wearing a standard shoe with 2 cm insole lift during gait (p<.05). When wearing a standard shoe with 2 cm insole lift, the total range of the pelvic segment were significantly different in all three motion planes (p<.05). Conclusion : Although LLD of less than 2 cm develops abnormal movement pattern of the pelvis and may cause of musculoskeletal diseases such as low back pain, hip and knee joint osteoarthritis, therefore intensive various physical therapy interventions for LLD are needed.

• Physical Therapy Korea
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• v.25 no.4
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• pp.9-18
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• 2018

Background: Leg length discrepancy (LLD) leads to many musculoskeletal disorders and affects daily activities such as walking. In the majority of the population, mild LLD is a common condition. Nevertheless, it is still controversy among researchers and clinicians on the effects of mild LLD during gait, and available studies have largely overlooked this issue. Objects: The purpose of the present study is to investigate the effects of mild LLD on the gait parameters and trunk acceleration. Methods: A total of 15 female and male participants with no evidence of LLD of >.5 ㎝ participated in the present study. All participants walked under the following two conditions: (1) The non-LLD condition, where the participants walked in shoes of the same heel height; (2) A mild LLD condition induced by wearing a 1.5 ㎝ higher heel on the right shoe. The GAITRite system and tri-axial accelerometer were used to measure gait parameters and trunk acceleration. To compare the variation of each variable, a paired t-test was performed. Results: Compared to the non-LLD condition, step time and swing phase were significantly increased in the mild LLD condition, while stance phase, single support phase, and double support phase significantly decreased in the short limb (p<.05). In the long limb of the mild LLD condition, single support phase significantly increased, while swing phase significantly decreased (p<.05). Furthermore, significant decrease in the gait velocity and cadence in the mild LLD condition were observed (p<.05). In the comparison between both limbs in the mild LLD condition, the step time and swing phase of the short limb significantly increased compared with the long limb, while step length, stance phase, and single support phase of the long limb significantly increased compared with the short limb (p<.05). Additionally, trunk acceleration of all directions (anterior-posterior, medial-lateral, vertical) significantly increased in the mild LLD condition (p<.05). Conclusion: The results of the present study demonstrate that mild LLD causes altered and asymmetrical gait patterns and affects the trunk, resulting in inefficient gait. Therefore, mild LLD should not be overlooked and requires adequate treatment.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.4
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• pp.171-183
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• 2010

Objectives : The biomechanical relationship of leg length discrepancy(LLD), Lumbar lordosis, pelvic variance and degenerative scoliosis is one of the most important parameters when treat musculoskeletal disorders, however the reports are still controversial. The purpose of this study was to compare the relationships between the parameters and bothersomeness in subject with chronic ow back pain. Methods : Sixty female and eight male adults with non specific low back pain over 3 months were recruited. LLD was measured by tape measure method. Lumbar lordosis, lumbosacral angle and related pelvic parameters were measured using simple radiologic films of lumbosacral view. Results : Lumbar lordosis was significantly correlated to the lumbosacral angle, pelvic incidence and difference of the both iliac widths. Pelvic incidence had significant correlation with difference of the both iliac widths. And difference of both iliac widths was related with LLD by radiologic film. There was also significant correlation between the LLD by radiologic film and tape measurement. Visual analogue scale(chronic low back pain) of normal lordosis group was greater than hyperlordosis group. Conclusions : There were close biomechanical relationships between lumbar, pelvis, and lower extremity. But in order to determine the effect of structure on the chronic low back pain, global balance of musculoskeletal structure seems to be worth further researching.

• Journal of Korean Physical Therapy Science
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• v.31 no.2
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• pp.30-40
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• 2024

Background: The purpose of this study is to identify the difference in muscle activity and muscle contraction onset time according to a LLD and object weight When subjects performed a lifting task. Design: Repeated measure design Methods: 15 male adults participated in this study. When subjects performed a lifting task, we measured a difference of muscle activity and muscle contraction onset time in the rectus abdominis(RA), the erector spinae(ES), and the rectus femoris(RF) between both legs using the surface electromyogram (Telemyo DTS, Noraxon Inc., USA). When subjects performed a lifting task, the weight of the object was set to 0% kg, 10% kg, and 20% kg of the subject's body weight, excluding the weight of the box. Results: The difference in muscle activity in the RA, the ES, and the RF between both legs when lifting an object was larger in LLD condition than in non-LLD condition(p<0.05). In all of muscles, the difference of contraction onset time was generally increased as the object's weight increased. Specially, the difference in muscle contraction onset time in the RA, the ES between both legs was larger in the LLD condition than in the non-LLD condition(p<0.05). Conclusion: This study suggests that LLD affects the muscle activity and muscle contraction onset time during lifting objects. It can be used as data to prevent joint damage and muscle due to the LLD during work and movements of daily living.