• The Journal of Korean Physical Therapy
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• v.34 no.2
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• pp.63-67
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• 2022

Purpose: The purpose of this study was to investigate the effect of assistance tools such as gym balls, wedges, and straps on lower extremity muscle activity and the increase in the range of motion made possible by the use of these tools. The subjects were divided into two groups: a group capable of deep-squatting (PS) and the second finding it impossible or having difficulty in performing such squats (IS). Methods: Twenty-three subjects participated in this study. Surface electromyography was used to measure the muscle activation of the rectus femoris (RF), vastus medialis (VM), and tibialis anterior (TA) muscles during deep squats, normal squats (NS), gym ball squats (GS), wedge squats (WS), and strap squats (SS). A motion analysis system was used to measure the range of motion of the knee joint during each of these exercises. Results: There was a significant difference in the RF muscle activity between the possible squat (PS) and the impossible squat (IS) groups in the GS, and there were significant differences in the RF and TA muscle activity between the groups in the WS. Both the PS group and the IS group showed a significant difference in the TA muscle activity depending on the tool used. There were also significant differences in the range of motion of the knee joints between the intervention methods using NS and those using the tools. Conclusion: In both groups, the muscle activity of the TA muscles was lower when GS, WS, and SS were performed compared to NS. In addition, compared to NS, the range of motion of the knee joint increased when the three tools were used. This study shows that the activity of the RF, VM, and TA muscles decreased and the range of motion of the knee joint increased during deep squats for both the PS and IS groups when tools were used.

• Korean Journal of Computational Design and Engineering
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• v.16 no.6
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• pp.391-396
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• 2011

Gait is walking attitude and indicating state. The body's gait is a good mix in the center of body mechanics and exercises to wake up gently at the same time switch is a pass which is complicated at legs various joints. The shifting action what swing phase and stance phase rhythmic movement of body. One from piece moves with different dot. Especially plain walking and stair walking as a vehicle has been used frequently. Characteristics of the stair walking while the balanced the horizontal and vertical movement. Stair walking often takes place in everyday. It requires large range more than walking at plain in the moment and joint range of gait motion. And consistently applied to joints and various types of loads at legs joint may involve joint disorders. In this study, spastic cerebral palsy existing artificial limbs for disabled people when developing calibration equinus deformity patients induce muscle pain when walking on stairs independently, to reduce the research. Comparing the characteristics of the walking up the stairs for analysis patellofemoral joint pain as a result it is to provide engineering data.

• The Korean Journal of Pain
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• v.28 no.2
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• pp.75-87
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• 2015

Background: Lumbar discogenic pain without pain mediated by a disc herniation, facet joints, or the sacroiliac joints, is common and often results in chronic, persistent pain and disability. After conservative treatment failure, injection therapy, such as an epidural injection, is frequently the next step considered in managing discogenic pain. The objective of this systematic review is to determine the efficacy of lumbar epidural injections in managing discogenic pain without radiculopathy, and compare this approach to lumbar fusion or disc arthroplasty surgery. Methods: A systematic review of randomized trials published from 1966 through October 2014 of all types of epidural injections and lumbar fusion or disc arthroplasty in managing lumbar discogenic pain was performed with methodological quality assessment and grading of evidence. The level of evidence was based on the grading of evidence criteria which, was conducted using 5 levels of evidence ranging from levels I to V. Results: Based on a qualitative assessment of the evidence for both approaches, there is Level II evidence for epidural injections, either caudal or lumbar interlaminar. Conclusions: The available evidence suggests fluoroscopically directed epidural injections provide long-term improvement in back and lower extremity pain for patients with lumbar discogenic pain. There is also limited evidence showing the potential effectiveness of surgical interventions compared to nonsurgical treatments.

• Korean Journal of Applied Biomechanics
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• v.27 no.2
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• pp.133-140
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• 2017

Objective: The purpose of this study was to determine the relationship between center of pressure (CoP) and local stability of the lower joints, which was calculated based on approximate entropy (ApEn) during walking in elderly women. Method: Eighteen elderly women were recruited (age: $66.4{\pm}1.2yrs$; mass: $55.4{\pm}8.3kg$; height: $1.56{\pm}0.04m$) for this study. Before collecting data, reflective marker triads composed of 3 non-collinear spheres were attached to the lateral surface of the thigh and shank near the mid-segment to measure motion of the thigh and shank segments. To measure foot motion, reflective markers were placed on the shoe at the heel, head of the fifth metatarsal, and lateral malleolus, and were also placed on the right anterior-superior iliac spine, left anterior-superior iliac spine, and sacrum to observe pelvic motion. During treadmill walking, kinematic data were recorded using 6 infrared cameras (Oqus 300, Qualisys, Sweden) with a 100 Hz sampling frequency and kinetic data were collected from a treadmill (Instrumented Treadmill, Bertec, USA) for 20 strides. From kinematic data, 3D angles of the lower extremity's joint were calculated using Cardan technique and then ApEn were computed for their angles to evaluate local stability. Range of CoP was determined from the kinetic data. Pearson product-moment and Spearman rank correlation coefficient were applied to find relationship between CoP and ApEn. The level of significance was determined at p<.05. Results: There was a negative linear correlation between CoP and ApEn of hip joint adduction-abduction motion (p<.05), but ApEn of other joint motion did not affect the CoP. Conclusion: It was conjectured that ApEn, local stability index, for adduction/abduction of the hip joint during walking could be useful as a fall predictor.

• Journal of the Ergonomics Society of Korea
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• v.35 no.5
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• pp.307-317
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• 2016

Objective: This study looks into biomechanical variables occurring when one moves in a sitting posture, and presents objective references to make improvements in work environments of farm workers. Background: The farmers have more common musculoskeletal disorders compared to other professions, because they are much more exposed to biomechanical risk factors. The sitting posture that is the representative form of the squatted, can cause typical knee joint diseases, such as osteoarthritis or patellofemoral pain syndrome of the knee joint. Therefore, a quantitative study of knee load upon the movement in a squatting posture is required. Method: In order to proceed with its investigation, the study examined movements in a sitting posture with and without a lower body supporter through a threedimensional image analysis and by using Surface EMG. The study compared and analyzed the average muscle activity and the maximum muscle activity as well. Results: Every movement in a sitting posture is related to loads onto the knee joints and, when the farm workers move to sides, the study observed a high level of bowlegged moment. The study also noticed differences in muscle activity of medial gastrocnemius with and without the lower body supporter. Conclusion and Application: The study argues that what has been discussed so far is evidence to prove how the farm working environments should be improved in consideration of these movements observed when the farm workers move in a sitting posture.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.131-138
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• 2014

The purpose of this study was to analyse the effect of the drop height on lower extremity and lower back kinematics and kinetics during drop landing with the use of raised heel insole. Furthermore we investigated the change that occurred in our body. Joint ROM, eccentric work and contribution to total work were calculated in 11 male college students performing drop landing with 8 motion analysis cameras and 1 forceplate. The result were as follows. First, the ROM and eccentric work were increased in all joints with the increase of the drop height. Second, the ankle ROM and eccentric work were decreased with the use of the insole. Third, the use of the lower back was increased as the use of the ankle decreased with the insole. Based on these results, we can infer that putting on the insole may contribute to chronic injury. We recommend not to use the insole during physical activity.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.395-406
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• 2010

The purpose of this study was to analyze the changes in kinematic and kinetic parameters of lower extremity joint according to rehabilitation period. Fourteen collegiate male athletes(age: $22.1{\pm}1.35$ years, height: $182.46{\pm}9.45cm$, weight: $88.63{\pm}9.25kg$) and fourteen collegiate athletes on functional ankle instability(age: $21.5{\pm}1.35$ years, height: $184.45{\pm}9.42cm$, weight: $92.85{\pm}10.85kg$) with the right leg as dominant were chosen. The subjects performed drop landing. The date were collected by using VICON with 8 camera to analyze kinematic variables and force platform to analyze kinetic variables. There are two approaches of this study, one is to compare between groups, the other is to find changes of lower extremity joint after rehabilitation. In comparison to the control group, FAI group showed more increased PF & Inversion at IC and decreased full ROM when drop landing. Regarding the peak force and loading rate, it resulted in higher PVGRF and loading. FAI group used more increased knee and hip ROM because of decreased ankle ROM to absorb the shock. And it used sagittal movement to stabilize. In terms of rehabilitation period, FAI group showed that landing patterns were changed and it increased total ankle excursion and used all lower extremity joint close to normal ankle. Regarding the peak force and loading rate, FAI group decreased PVGRF and loading rate. and also showed shock absorption using increased ankle movement. And COP variable showed that proprioception training increased stability during 8 weeks. The results of this study suggest that 8 weeks rehabilitation period is worthwhile to be considered as a way to improve neuromuscular control and to prevent sports injuries.

• Proceedings of the ESK Conference
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• 1994.04a
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• pp.136-144
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• 1994

In this study, the human gait trajectories during normal walking were synthesized using the inverse kinematics and optimization techniques. The synthesis based on a lower extremity model consisting of a torso and two legs. Each leg has three segments: thigh, shank, foot, and is assumed to move with six degrees-of-freedom. In order to synthesize trajectiories of this redundant system, the sum of angular displacements of articulating joints was selected as an objective function to be minimized. The proposed algorithm in this study is very useful for the analysis of human gait. For the gait analysis, the trajectories of four points in each leg should be measured. However, by using the algorithm, measuring the trajectories of two points is sufficient, and thus the experimental set-up can be simplified. The predicted joint trajectories showed a good agreement with those obtained from the experiment. The statistical analysis and graphic simula- tions are also presented.

• Advances in biomechanics and applications
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• v.1 no.1
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• pp.57-66
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• 2014

The purpose of the study was to investigate the kinematics between the double collar-tie and double underhook Thai Boxing clinching positions. Ten amateur mixed martial arts athletes executed six knee strikes for both clinching positions with their dominant limb directed towards a target. A standard two-dimensional video motion analysis was conducted, and the results showed a statistical significant difference at the hip joint angle and the angular acceleration of the knee and ankle. Within both clinching positions, there was a statistically significant correlation between the hip and knee joint angles, hip and knee angular velocities, and hip angular acceleration. Between both clinching positions, there was a statistically significant correlation at the knee joint angle, knee angular velocity, and hip angular acceleration. This study demonstrates the importance of the hip and knee joint movements in both clinching positions, which implies the applications of strength training and flexibility at these joints for sports performance and injury prevention. It is suggested that future studies analyzing the non-dominant leg are warranted to fully understand the Thai Boxing clinch.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.173-179
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• 2011

This study aims to analyse difference in biomechanical factors between dominant legs and recessive ones according to muscular imbalance during drop landing targeting talented children in sports. The subjects of the study were ten primary students who are attending to Sports Program for Talented Children organized by C university (age: $12.28{\pm}0.70$ year, height: $1.52{\pm}0.11$ m, and weight: $45.2{\pm}4.9$ kg). Strength legs were classified into dominant side and strengthless legs were classified into non-dominant legs. For three-dimensional analyses of the data collected, 6 video cameras(MotionMaster200, Visol, Korea) were used. To analyse ground reaction force, two force platforms(AMTI ORG-6, MA) were used and to analyse electromyograghy a 8-channeled wireless Noraxon Myoresearch made in USA was used at 1000 Hz for sampling. As a result, it was discovered that the dominants legs controlled knee bending motions more stably than strengthless legs as the maximum vertical ground reaction force was significantly high in dominant legs(p<.05), and joint moment of knee joints of the dominant legs was high(p<.05). Therefore, this study suggested that injury prevention program focusing on muscular balance as well as the existing sports programs for talented children should be developed based on results of the study and it is expected that the results will be useful for improvement of sports programs for talented children.