• 한국체육학회지인문사회과학편
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• v.54 no.5
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• pp.769-780
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• 2015

This study investigated the changes in inflammatory mediators, immunocompetent cells and bone merrow progenitor cells by the magnitude of muscle damage and type of the muscle contraction in the elderly. Twenty older adults who had not been involved in a resistance-training program at least 6 months prior to the present study were assigned to eccentric exercise group (ECC, n=10) and concentric exercise group (CON, n=10). All subjects performed 10 sets of 6 maximal isokinetic eccentric (ECC 1) or concentric (CON) contractions with the non-dominant arm in a randomized, with 4 wk between bouts (ECC 2). Skeletal muscle damage index (ROM, VAS, Plasma CK), inflammation mediators (TNF-α, IL-1, IL-6), immunocomperent cells (CD3+, CD4+, CD8+, CD19+), bone merrow progenitor cell (CD34+) and leukocytes were measured before, immediately after, 2, 24, 48, 72, and 96 h after exercise. Changes in ROM and VAS were greater (P<.05) after ECC 1 than CON and ECC 2. Increases in TNF-α and IL-6 were greater (P<.05) 24, 48 and 72 h after ECC 1 than CON and ECC 2. Increases in neutrophils were greater (P<.05) 2 h after ECC 1 than CON and ECC 2. It was confirmed that muscle damage was greater following eccentric than concentric contractions as well as first bout than second bout in the elderly, and suggested that TNF-α, IL-6 and neutrophils should closely correlate with magnitude of muscle damage.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.197-206
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• 2005

The purpose of this study was to quantify the maximum EMG levels and determine if there are differences in these EMG levels with respect to different knee flexion angles. Eight university students with no known musculoskeletal disorders were recruited as the participants. The maximum voluntary isometric knee extensions and flexions were taken from each participant sat on the isokinetic exercise machine (Cybex 340) at five different knee flexion angles ($10^{\circ}$, $30^{\circ}$, $50^{\circ}$, $70^{\circ}$, $90^{\circ}$) After surface electrodes were attached to rectus femoris, vastus medialis, vastus laterlis, biceps femoris, and semitendinosus, maximum EMG levels at five different knee flexion angles were measured. The results showed that there was no significant difference in maximum EMG levels among five different knee flexion angles. Although there was no significant difference in EMG levels and were some variations among different knee flexion angles, the EMG signals of quadriceps in extension and biceps femoris in flexion were the greatest at $30^{\circ}$. It seems that different joint angles or relative locations of body segments might affect the magnitude of EMG levels. Because the maximum EMG levels could change with a different knee flexion angle, an attempt should be made to more accurately measure these values. If then, %MVIC measure provides more reliable data and is most appropriate for EMG normalization.

• Physical Therapy Korea
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• v.22 no.2
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• pp.1-10
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• 2015

The common features of walking in patients with stroke include decreased gait velocity and increased asymmetrical gait pattern. The purpose of this study was to identify important factors related to impairments in gait velocity and asymmetry in chronic stroke patients. The subjects were 30 independently ambulating subjects with chronic stroke. The subjects' impairments were examined, including the isokinetic peak torque of knee extensors, knee flexors, ankle plantarflexors, and ankle dorsiflexors. Passive and active ranges of motion (ROM) of the ankle joint, ankle plantarflexor spasticity, joint position senses of the knee and ankle joint, and balance were examined together. In addition, gait velocity and temporal and spatial asymmetry were evaluated with subjects walking at their comfortable speed. Pearson correlations and multiple regressions were used to measure the relationships between impairments and gait speed and impairments and asymmetry. Regression analyses revealed that ankle passive ROM and peak torque of knee flexors were important factors for gait velocity ($R^2=.41$), while ankle passive ROM was the most important determinant for temporal asymmetry ($R^2=.35$). In addition, knee extensor peak torque was the most significant factor for gait spatial asymmetry ($R^2=.17$). Limitation in ankle passive ROM and weakness of the knee flexor were major contributors to slow gait velocity. Moreover, limited passive ROM in the ankle influenced the level of temporal gait asymmetry in chronic stroke patients. Our findings suggest that stroke rehabilitation programs aiming to improve gait velocity and temporal asymmetry should include stretching exercise for the ankle joint.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.2
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• pp.139-147
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• 2020

Purpose : Proprioceptive position sense plays a key role in providing joint stability, and multiple factors are related to proprioceptive position sense. Thus, this study aimed to determine the effects of body composition, particularly skeletal muscle mass on proprioceptive position sense following muscle fatigue. Methods : Healthy female subjects agreed to have their body composition analyzed. Only subjects who had 18.5-22.9 kg/㎡ of BMI (body mass index) were included in this study, and the participants were divided into two groups by skeletal muscle mass level. The experimental group had a level of skeletal muscle lower than the standard level (n=9), while the control group showed a standard or high level of skeletal muscle mass (n=11). To determine the change in proprioceptive position sense of the knee joint, the absolute angle error (AAE) was evaluated following muscle fatigue on low extremity. The muscle fatigue was induced by isokinetic resistance exercise program of Biodex system. AAE was measured by the Biodex system and compared the result before and after muscle fatigue. Results : The experimental group showed a significant AAE difference between before (3.16±2.48 °) and after (5.40±2.61 °) muscle fatigue. In addition, there was a AAE difference between the experimental (5.40±2.61 °) and control groups (3.53±1.67 °) after fatigue; however, there was no significance. Those results indicated that low level of skeletal muscle mass might influence the proprioceptive position sense of the knee joint after muscle fatigue. Conclusion : Thus, maintaining the proper level of skeletal muscle mass is pivotal to reduce the risk of injury following muscle fatigue in ADL or sport activities.

• Journal of the Korea Convergence Society
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• v.13 no.5
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• pp.307-312
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• 2022

The purpose of this study was to investigate the effects of wearing functional clothing over calf muscles on the muscle function of the calf and to verify whether functional clothing can increase calf muscle function. The participants of the study were 21 male students from University B who had no lower extremity abnormality. The measurement method was measured at 30°/sec and 120°/sec angle speed before and after wearing functional clothing on the right and left calves using Humac Norm of CSMI, a constant speed muscle function measuring instrument. No significant difference was observed during dorsiflexion when wearing functional clothing, but in plantar flexion, muscle strength and muscle endurance were significantly increased. Therefore, wearing functional clothing over the calves showed a positive effect on improving exercise function, and future research suggests a study comparing the degree of muscle function improvement between those wearing functional clothing and those not wearing it for athletes training ahead of the competition.

• Journal of Korean Physical Therapy Science
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• v.29 no.4
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• pp.27-42
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• 2022

Background: Although children with cerebral palsy (CP) are able to walk independently, gait imbalance occurs due to abnormal muscle tone, musculoskeletal deformity, loss of balance, and selective motor control impairment. Gait restriction in the community and school is a major problem of rehabilitation in CP. Home-based therapy (HBT) provides a variety of interventions in which the therapist and the parent work together to resolve the activities and problems caused by the child's body structure. Therefore, we investigate the effectiveness of home-centered therapy on gross motor function in CP and try to present the possibility of clinical application. Design: A Systematic Review Methods: Research papers were published from Jan, 2012 to Jan, 2022 and were searched using Medline and PubMed. The search terms are 'family-centered' OR 'home-based' AND 'cerebral palsy'. A total of nine papers were analyzed in this study. The paper presented the quality level based on Physiotherapy Evidence Database (PEDro) scores to assess the quality of randomized clinical trials studies. Results: The results showed that HBT for strengthening exercise in lower extremity has a positive effect on the isokinetic torque and gross motor function. home-based treadmill therapy in CP is effective to perform at least 12 sessions of treadmill HBP in which the therapist determines the treadmill speed every week and the child's own gait pattern is modified. Conclusion: These results suggest that it will be important data for founding evidence on the effectiveness of home-centered therapy on gross motor function in children with cerebral palsy to advance clinical protocols.

• Journal of the Korean Applied Science and Technology
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• v.41 no.3
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• pp.813-824
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• 2024

This study was conducted to evaluate the long-term effects of training on the physical development and exercise performance of adolescent weightlifters, aiming to provide effective training and management strategies for improving competitive performance. In order to achieve the objectives of the study, adolescent weightlifters from middle and high schools in Chungcheongnam-do province [male middle school-aged athletes, n=5; female middle school-aged athletes, n=5; male high school-aged athletes, n=12; female high school-aged athletes, n=8] were examined over approximately 10 months of weightlifting-based training to analyse the changes in body composition, physical fitness (muscular strength, muscular endurance, agility, flexibility, dynamic balance, coordination), and isokinetic muscular function (trunk and lower extremity). As a result, it was found that the physical development of middle and high school-aged athletes underwent physical development primarily characterized by an increase in lean body mass. Additionally, back muscle strength and power, which contribute to rapid and efficient force transmission between the upper and lower body, as well as grip strength necessary for controlling the barbell with a stable grip, are significant factors. These aspects were notably enhanced through specialized training and competitive experience for weightlifting performance at the high school level. On the other hand, changes in factors beyond the primary physical attributes contributing to weightlifting performance were limited, suggesting differences in effectiveness likely stemming from the specific composition of training programs or the athletes' experience and skill levels. Collectively, the findings from this study, which evaluates the physical characteristics and exercise abilities of adolescent weightlifters, are expected to contribute to improved competitive performance of weightlifters.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.343-351
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• 2015

Objective : The purpose of this study was to investigate the effects in the muscle function following 8-week dead-lift training with Whole-body Vibration(WBV) in rehabilitation for sports players. Method : Twenty young sports players. Each subjects were randomly assigned to a resistance training with Whole-body vibration group(TG, n=10), a resistance training without Whole-body vibration group(CG, N=10). The measurements which physical fitness test and joint torque test were performed before the randomization and after the 4-week and 8-week. The WBV group performed the dynamic Dead-lift exercise on a vibration platform during one minute. The CG group performed the equal training without vibration. The WBV and CON group repeated 5 set and trained two times weekly for 8-weeks. Paired t-test was used to test for differences between the groups at baseline and after 4-weeks and 8-Weeks. And independent t-test was used to test for differences between the groups at TG and CG. All analyses were executed using SPSS software 18.0. The level of significance was set at p<.050. Results : Following the 8-Weeks training sessions, an increase in the back-muscle strength was found to be greater for the TG compared with the CG group(p<.05). Muscle endurance was significantly decreased after training than before training only for the CG(p<.05). Isometric Hip/Lumber Extension/Flextion measurement was found to be significantly greater for the TG compared with the CG group(p<.05). The finding indicates that WBV effects as an efficient training stimulus to enhance muscle function by facilitating neural control trail. Following muscle activation in motor unit synchronization of the co-contraction of the muscles. Conclusion : The results imply that the WBV training may have enhanced muscle function in rehabilitation for sports players.

• 한국체육학회지인문사회과학편
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• v.54 no.1
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• pp.535-544
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• 2015

This study was performed to determine the effect of low-intensity resistance training with blood flow restriction (BFR) on muscle volume and strength in elderly women. Sixteen elderly women (70.9±4.6 years) were divided into low (30% 1RM) and high (75% 1RM) intense resistance training groups. Tourniquet cuff (Zimmer, Germany) for BFR was applied only to the right leg during the training period. All subjects performed unilateral leg press, leg extension and leg curl (3 sets×12 repetitions) for 10 weeks (2d/wk). Blood pressure was increased from 110 to 240 mmHg during the training period at the most proximal region of exercised leg. Muscle volume and cross-sectional area (CSA) were measured by MRI and body composition was monitored by dual-energy X-ray absorptiometry (DEXA) and isokinetic muscular strength were analyzed in both legs. The quadriceps CSA (15.2%, p<.001) and muscle volume (13.8%, p<.001) were increased in high-intense trained leg with BFR and the increased rate was highest among groups. The quadriceps CSA (9.8%, p<.001) and muscle volume (6.9%, p<.001) were increased in low-intensity training group with BFR and their increased rates were higher than control groups. The strength by exercise training was significantly improved in all groups and tended to be higher in BFR groups. These results demonstrate low-intensity resistance training with blood flow restriction could be an effective way to improve muscle volume and strength in elderly women.

• The Journal of Korean Physical Therapy
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• v.18 no.6
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• pp.1-11
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• 2006

Purpose: This study compared the effects of non-cold and cold conditions on the viscoelastic properties of tendon structures in vivo. Methods: Seven male subjects perfomed plantar flesion exercise with maximal isokinetic voluntary contraction, which consisted of muscle contraction for 6 see and relaxation for 60 secs, 10 times for 1 set, Totally 10 sets were repeated. Before and after each task, the elongation of the tendon and aponeurosis of the medial gastrocnemius muscle (MG) was directly measured by ultrasonography. (The relationship between the estimated tendon force and tendon elongation.) Tendon cross-sectional area and ankle joint moment arm were obtained from magnetic resonance imaging (MRI). The tendon force was calculated from the joint moments and the tendon moment arm and stress was obtained by dividing force by cross-sectional areas (CSA). The strain was measured from the displacements normalized to tendon length. Results: After cooling, the tendon force was larger in cold than non-cold. The value of the tendon stiffness of MVC were significantly higher under the cold condition than under the non-cold condition. The maximal strain and stress of $7.4{\pm}0.7%$ and $36.4{\pm}1.8$ MPa in non-cold and $7.8{\pm}8.5%,\;31.8{\pm}1.1$ MPa in cold (P<0.05). Conclusion: This study shows for the first time that the muscle endurance in cooling increases the stiffness and Young's modulus of human tendons. The improvement in muscle endurance with cooling was directly related to muscle and tendon.