• Physical Therapy Korea
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• v.22 no.4
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• pp.8-16
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• 2015

The purpose of this study was to evaluate the effects of mobilization of the sciatic nerve on hamstring flexibility, lower limb strength, and gait performance in patients with chronic stroke. This study was a randomized clinical trial with a crossover design. Sixteen subjects were recruited for this study. The subjects were randomly divided into two intervention groups and underwent either of the following two interventions: sciatic nerve mobilization or static stretching of the hamstring. We assessed hamstring flexibility, lower limb strength, and gait performance using a digital inclinometer, a hand-held dynamometer, and the 10-meter walk test, respectively. Subjects had a 24-hour rest period between each session in order to minimize carryover effects. Measurements for each test were assessed prior to and immediately after the intervention sessions. Using a two-way analysis of variance test with repeated measures, data from the two trials were analyzed by comparing the differences between both techniques. The level of statistical significance was set at .05. Sciatic nerve mobilization resulted in significantly better knee extensor strength (p=.023, from $15.32{\pm}5.98$ to $18.16{\pm}6.95kg$) and knee flexor strength (p=.011, from $7.80{\pm}4.80$ to $8.15{\pm}4.24kg$) in the experimental group than in the control group. However, no significant effects of static stretching of the hamstring were observed on hamstring flexibility from the ankle plantar flexion (p=.966) and ankle neutral positions (p=.210) and on gait performance (p=.396). This study indicated that the sciatic nerve mobilization technique may be more effective in muscle activation of the knee extensor muscle and knee flexor muscle than hamstring static stretching technique in patients with chronic stroke.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.2
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• pp.2090-2095
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• 2020

Background: Spinal Mobilization is one of the manual therapy technique that clinicians have used to treat pain, however, there is still a lack of research on changes in strength in healthy people. Objectives: To investigate the effect of posterior-anterior lumbar mobilization on lower limb strength in healthy individuals. Design: Two-group pretest-posttest design. Methods: In this study, 23 healthy subjects aged 20 years were assigned to 12 lumbar mobilization group (LMG) and 12 sham group (SG) to perform intervention and measurement through pre- and post-design. Intervention was performed in LMG with grade III~IV on L3-5 of the lumbar spine, and lumbar mobilization was performed for each segment. After intervention, knee flexion and extension strength were measured. To measure the main effect on muscle strength, a comparative analysis was conducted using paired t-test and independent t-test. Results: In LMG, knee flexor and extensor strength were increased significantly at 60°/s (P<.05). In addition, the extensors of LMG and SG were significantly different only at 60°/s, and the flexors were significantly different between groups at both 60°/s and 180°/s (P<.05). Conclusion: In healthy individuals, lumbar mobilization results in improvement of strength of knee flexor and extensor, and additional experiments on the effect of mobilization on the lumbar spine on functional changes in the lower limbs will be needed.

• Physical Therapy Korea
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• v.26 no.2
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• pp.69-75
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• 2019

Background: Knee osteoarthritis (OA) diagnosis using Kellgren-Lawrence scores is commonly used to help decision-making during assessment of the severity of OA with assessment of pain, function and muscle strength. The association between Kellgren-Lawrence scores and functional/clinical outcomes remains controversial in patients with knee OA. Objects: The purpose of this study was to examine the relationships between Kellgren-Lawrence scores and knee pain associated with OA, function during daily living and sports activities, quality of life, and knee muscle strength in patients with knee OA. Methods: We recruited 66 patients with tibiofemoral knee OA and determined knee joint Kellgren-Lawrence scores using standing anteroposterior radiographs. Self-reported knee pain, daily living function, sports/recreation function, and quality of life were measured using the knee injury and OA outcome score (KOOS). Knee extensors and flexors were assessed using a handheld dynamometer. We performed Spearman's rank correlation analyses to evaluate the relationships between Kellgren-Lawrence and KOOS scores or muscle strength. Results: Kellgren-Lawrence scores were significantly negatively correlated with KOOS scores for knee pain, daily living function, sports/recreation function, and quality of life. Statistically significant negative correlations were found between Kellgren-Lawrence scores and knee extensor strength but not flexor strength. Conclusion: Higher Kellgren-Lawrence scores were associated with more severe knee pain and lower levels of function in daily living and sports/recreation, quality of life, and knee extensor strength in patients with knee OA. Therefore, we conclude that knee OA assessment via self-reported KOOS and knee extensor strength may be a cost-effective alternative to radiological exams.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.73-81
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• 2006

The purpose of this study was to investigate the effects of strength training on knee joint torque during walking in an adolescent with trisomy-21 Down syndrome. One adolescent with Down syndrome and one normal child participated in this study. Strength training consisted of eight exercises: squat, hamstring curl, hip adduction, hip abduction, knee extension, toe raise, sit-ups, and hyperextension of the waist. The participant with Down syndrome was participated in strength training for 12 weeks, three times a week, three sets, 10-15 RM; resistance was adjusted according to the principle of progressive overload. To measure the effect of strength training, isokinetic strength variables and knee joint torques were measured before training and after 12 weeks of training. The participant with Down syndrome had some abnormalities in controlling knee motion during walking due to muscle hypotonia, ligament laxity, and weakness of muscles. Post-training isokinetic strength increased compared to pre-training measurements. Knee range of motion were increased after strength training. Strength training did not affect ad/adduction and in/exteranl moments but did have an effect on flexor/extensor moment and timing.

• The Journal of Korean Physical Therapy
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• v.11 no.1
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• pp.129-136
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• 1999

The purpode of this study was to determine the EMG characteristies of 7 subjects with hemiplegic gait receiving therapeautic exercise after stroke. The akin electrode and gait analysis system were used. The normal gait of 6 health volunteers was analysised. The results were following. 1. Gluteus maximus, the extensor of hip joint had high level of activity compared to normal, and had two peak in late stance phase and early Swing phase. 2. Medial hamstring, the flexor of knee joint had low level of activity compared to normal, and had continuous low amplitude pattern. 3. Vastus lateralis, the extensor of knee joint had high level of activity compared to normal, and had not continuous high amplitude. From early stance phase and mid stance phase, activity had high level but after swing phase. similar to normal. 4. Gastrocnemius, plantar flexor of ankle joint had low level of activity compared to normal and had continuous low amplitude. 5. Tibialis anterior, dorsiflexor of ankle joint had similar muscle activity to normal and had continuous low amplitude.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.3
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• pp.127-133
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• 2020

PURPOSE: The study examined the relationship between the knee function score and knee strength and muscular endurance of an elite female handball athletes according to their position in the team. METHODS: Thirty handball athletes participated on the study: 12 front positions, 12 back positions, and five goalkeepers. The knee function score consisted of symptoms, pain, daily activity, sports and recreation, and quality of life. In addition, CSMI (Cybex, USA) was used to measure the strength and muscular endurance of the knee. The muscular strength and muscular endurance were measured at an angular velocity of 60°/s and 180°/s, respectively. RESULTS: The overall items of the knee function score showed a significant difference (p = .017), and goalkeepers had significantly higher scores than the back positions. In addition, significant differences were observed in all five items depending on the position (p ≤ .05). On the other hand, both the flexor and extensor muscles of the knee strength and muscular endurance were not significant. Moreover, there was no correlation between the knee function score and the knee strength and muscle endurance. CONCLUSION: Elite female handball athletes have different knee functions score depending on their position in the team, but the, strength and muscular endurance of the knee were similar for each position. Furthermore, the knee function score showed no correlateion with the strength and muscular endurance of the knee.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.4
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• pp.1-8
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• 2019

PURPOSE: The purpose of this study was to compare the maximum knee strength and endurance of elderly Korean women with Kellgren-Lawrence grade (K-L II) by age. METHODS: In this study, the total number of participants was 50, divided into five groups of 10 by age. Maximum knee muscle strength was measured at a low speed of 60°/sec using Biodex, an isokinetic device for comparison of maximum knee muscle strength, whereas muscle endurance was measured by muscle contraction at a high speed of 180°/sec. The peak torque values of the extensor and flexor muscles in the muscle strength and muscle endurance tests were collected according to each classification. RESULTS: The results of the experiment show that maximum muscle strength and muscle endurance decreased significantly at 60°/sec and 180°/sec during flexion and extension according to age (p<.05). In particular, the age group of 71 to 75 years showed the most significant correlation with other age groups (p<.05). CONCLUSION: The results of this study can be used as basic data for increasing physical activity and muscle strength in women with knee osteoarthritis.

• Journal of the Ergonomics Society of Korea
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• v.29 no.3
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• pp.357-364
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• 2010

This study proposes a lower-limb exoskeleton system that is controlled by a wearer's muscle activity. This system is designed by following procedure. First, analyze the muscle activation patterns of human leg while walking. Second, select the adequate actuator to support the human walking based on calculation of required force of knee joint for step walking. Third, unit type knee and ankle orthotics are integrated with selected actuator. Finally, using this knee-assistive system (KAS) and developed muscle stiffness sensors (MSS), the muscle activity pattern of the subject is analyzed while he is walking on the stair. This study proposes an operating algorithm of KAS based on command signal of MSS which is generated by motion intent of human. A healthy and normal subject walked while wearing the developed powered-knee exoskeleton on his/her knees, and measured effectively assisted plantar flexor strength of the subject's knees and those neighboring muscles. Finally, capabilities and feasibility of the KAS are evaluated by testing the adapted motor pattern and the EMG signal variance while walking with exoskeleton. These results shows that developed exoskeleton which controlled by muscle activity could help human's walking acceptably.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.7 s.196
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• pp.133-138
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• 2007

It is important to understand the characteristics of amputee gait to develop more advanced prostheses. The aim of this study was quantitatively to analyze the stair climbing task for the above-knee amputee with a prosthesis and to predict muscle forces and joint moments at musculoskeletal joints by dynamic analysis. The three-dimensional musculoskeletal model of lower extremities was constructed by gait analysis and transformation software for one above-knee amputee and ten healthy people. The measured ground reaction forces and kinematical data of each joint by gait analysis were used as input data during inverse dynamic analysis. Lastly, dynamic analysis of above-knee amputee during stair climbing were performed using musculoskeletal models. The results showed that summed muscle farces of hip extensor of amputated leg were greater than those of sound leg but the opposite results were revealed at hip abductor and knee flexor of amputated leg. We could also find that the higher moments at hip and knee joint of sound leg were needed to overcome the flexion moment caused by body weight and amputated leg. In conclusion, dynamic analysis using musculoskeletal models may be a useful mean to predict muscle forces and joint moments for specific motion tasks related to rehacilitation therapy..

• Physical Therapy Korea
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• v.14 no.3
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• pp.23-31
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• 2007

The purpose of this study was to determine the influence of high-heeled shoes on walking of obese women as it was already proven an extrinsic factor of knee osteoarthritis in women with normal weight. In this study the aimed therefore in particular was to utilize high-heeled shoes in proving it's causal influence on knee osteoarthritis by measuring the angle and torque of the knee joint. Fifteen obese women (BMI>25 $kg/m^2$) were measured in their twenties. Each angle and torque of their knee joints during walking on 6.5 cm high-heeled shoes and with a bare feet, were compared with each other and analyzed with a 3D motion analysis system. There was no significant difference in walking speed, cadence and stride length between the two conditions. However, there was a significant increase in a double limb support time and the stance phase when walking on high-heeled shoes as when walking with bare feet. The peak knee flexion angle and peak knee varus torque was higher when walking on high-heeled shoes than with bare feet. On the contrary, the peak knee flexion angle in the swing phase was not statistically different. The prolongation of peak knee varus torque was also proven. There was a significant increase in peak knee varus torque in the initial and last stance phases during walking on high-heeled shoes as compared to walking on bare feet. Through the above results, it was proven that when obese women walked on high-heeled shoes, rather than with bare feet, peak knee flexor and varus torque increased along with the changes of the in knee joint angle. Therefore, the influence of high-heeled shoes might be a significant intrinsic factor in knee osteoarthritis of obese women.