• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.107-115
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• 2008

The purpose of this study was to investigate muscle activity and vertical ground reaction force(F) in children with Down syndrome(DS) during vertical jump. Six DS and one healthy child performed vertical jump. Four muscles(Biceps femoris, Rectus femoris, Tibialis anterior & Gastrocnemius) and F were analyzed. Gastrocnemius in DS showed lower muscle activity in a propulsive phase. Impulse during 0.3sec before toe-off in DS displayed lower value than that in the healthy child. The second peak of F in DS occurred later than that in the healthy child, so DS performed landing with their knee more flexed. The first and second peak of F and loading rate to the second peak of F in DS showed lower value than those in the healthy child. Therefore, DS might have lower ability to absorb the force while landing from a vertical jump.

• Journal of Korean Biological Nursing Science
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• v.18 no.2
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• pp.102-109
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• 2016

Purpose: The purpose of this study was to describe sports injuries among elderly people and to compare physical activity, perceived health status and exercise self-efficacy between elderly people who had experienced a sports injury and elderly people who hadn't. Methods: The sample of this study were 100 elderly in Korea, 51 of whom had had a sports injury. The study used questionnaires to gather data. There were 8 demographic factors, 4 factors related to physical activity, perceived health status and exercise self-efficacy of the subjects. Data were analyzed by frequencies, chi-square test, and t-test. Result: Among the sports injured elders, one occurrence of a sport injury was 86.3%. There were more outdoor than indoor sports injuries of elders (66.7%), and sports injuries of elders occurred more in the winter (82.7%). The major cause of the sports injuries was loss of balance. Ankles were frequently damaged from these injuries. The most significant change after the sports injury was reduction of physical activity (60.8%). There were significant differences between sports injured elderly and non-injured elderly for age (${\chi}^2=2.58$, p=.011) and the amount of physical activity (t=1.96, p=.050), but there was no significant difference in perceived health status and exercise self-efficacy. Conclusion: To prevent sports injuries in the elderly means to maintain a medium level of physical activity and to improve their balance.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.667-675
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• 2016

This study aims to investigate the effects of regular participation in physical activity on personal happiness by analyzing the "2014 National Leisure Sports Participation Survey". By using cross-tabulation and the binary logit model, it is found that there is a positive correlation between those two variables. The effect of positive affect on happiness index was found to be influenced by age, education level, occupation, income, marital status, appear. The results of the analysis of the relationship between the presence of sports facilities and the participation of regular physical activity using crosstab analysis and the analysis of physical activity showed positive relationship between two variables. Hence, it is expected that providing more opportunities to participate in sports programs can lead the public to more regular participation in physical activity.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.24 no.2
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• pp.1-7
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• 2018

Background: This study was carried out to investigate the effect of mulligan taping group and repeated measurement group on muscle activity and grip strength of adult with forward head posture. Methods: Thirty adults with forward head posture were randomly assigned to each of 15 mulligan taping and repeat measurement groups. The mulligan taping group measured the pre-test and post-test muscle activity and the grip strength three times and compared the mean values. The repeat group was repeatedly measured and measured before and after the experiment, The collected data were analyzed using SPSS statistical program. Results: There was no significant difference between mulligan taping group and repeated measurement group in changes of muscle activity. There was a significant difference between mulligan taping group and repeated measurement group in changes of grip strength. Conclusions: Mulligan taping was applied to an adult with forward head posture, there was no significant change in muscle activity of flexor carpi radialis and palmaris longus, but it seems to improve hand function by re-aligned of nearby muscles by maintaining scapular stability.

• Journal of Sport and Applied Science
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• v.7 no.1
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• pp.21-29
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• 2023

Purpose: This study was to investigate the effects of isometric exercise on muscle activity and body balance ability in asymmetrical walkers. Research design, data, and methodology: Twenty gait asymmetry people were divided to unilateral exercise group (UG, n=10) and bilateral exercise group (BG, n=10). UG were performed unilateral exercise for 60 minutes, three times a week, and 16 weeks, and BG were performed one side and then the other side alternately for 60 minutes, three times a week, and 16 weeks. Muscle activity and body balance ability were measured before, after 4 and 16 weeks isometric exercise. Moreover, SI (symmetry index; SI) was calculated from the measured value of SL (step length). Statistical analyses were conducted using one-way ANOVA and two-way ANOVA with repeated measures, a paired t-test, and multiple comparisons according to Scheffe. Results: In the muscle activity, ST decreased significantly in short step length(S-SL) and BG of LS compared to before isometric exercise(p<.05), and GCM decreased significantly in BG of S-SL(p<.05). As for body balance ability, the mSEBT-A difference between L-SL and S-SL was decreased significantly in UG(p<.05). And the respective total scores of L-SL and S-SL, mSEBT-PM and mSEBT-PL were increased significantly in BG(p<.05). Conclusions: As a result, in this study above, it was confirmed that isometric exercise improved muscle activity and body balance ability in asymmetrical walkers.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.469-477
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• 2010

The purpose of this study was to evaluate the effects of insole-equipped ankle-foot-orthoses (AFO) on gait. 10 healthy males who had no history of injury in the lower extremity participated in this study as the subjects. The foot of each subject was first scanned, and the insole fit to the plantar was made using BDI-PCO(Pedcad Gmbh, Germany). The subject then was made to walk on a treadmill under four experimental conditions: 1) normal walking, 2) walking wearing AFO, 3) walking wearing AFO equipped with the insole, 4) walking wearing pneumatic-ankle-foot-orthosis (pAFO) equipped with the insole. During walking, foot pressure data such as maximum force, contacting area, peak pressure, and mean pressure was collected using Pedar-X system (Novel Gmbh, Germany) and EMG activity of lower limb muscles such as gastrocnemius medial head, gastrocnemius lateral head, and soleus was recorded using MP150 EMG module (BIOPAC System Inc., USA). Collected data was then analyzed using paired t-test in order to investigate the effects of the insole. As a result of the analysis, when insole was equipped, overall contacting area was increased while both the highest peak pressure and the mean pressure were significantly decreased, and EMG activity of the lower limb muscles was decreased. On the contrary, the cases of wearing AFO showed the decreased contacting area and the increased pressures. Therefore, the AFO equipped with a proper insole fit well to the foot can help comfortable walking by spreading the pressure over the entire plantar.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.139-149
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• 2014

The purpose of this study was to evaluate the effect of angle change of forefoot's adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over $-20^{\circ}$ ramp. Thirteen male university students (age: $25.4{\pm}3.9$ yrs, height: $176.2{\pm}5.1$ cm, weight: $717.4{\pm}105.0$ N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site pre-amplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over $0^{\circ}$ and $20^{\circ}$ ramp with three different forefeet's EVA outsole (0, 10, $20^{\circ}$) in random order at a speed of $1.2{\pm}0.1$ m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in $20^{\circ}$ shoes compared to $0^{\circ}$ and $10^{\circ}$ ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot's adhesive outsole, indicating that the increment of shoes' angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in $20^{\circ}$ outsole compared to $0^{\circ}$ and $10^{\circ}$ ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

• Journal of Digital Convergence
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• v.15 no.3
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• pp.365-373
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• 2017

This research aims to verify the moderating effect of sports activity satisfaction in the relationship between adolescents' communication skills and positive self-concept within peer group. To achieve this purpose, this study extracted 250 samples from five boys high schools in Gyeonggi-do, and used survey of 232 students for actual analysis excluding the surveys with unfaithful answer or double entry. Questionnaire was used as a tool for collecting data and conducted frequency analysis, correlation analysis and moderator regression analysis to analyze the collected data. This study drew the following results. It was identified that sub-factors of sports activity satisfaction as social, physical, environmental and educational satisfaction have the moderating effect in the relationship between adolescents' communication skills and social self-concept with peer group. In other words, communication skills within adolescents' peer group play an important role in improving positive self-concept, but when sports activity satisfaction put as a moderating variable, adolescents' positive self-concept would be more improved.

• Korean Journal of Applied Biomechanics
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• v.33 no.1
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• pp.10-16
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• 2023

Objective: The purpose of this was to find out the muscle activity of the quadriceps femoris by gender when sitting on a chair while performing stairs gait (US; Up-stairs, DS; Down-stairs). Method: 13 male subjects (age: 22.00 ± 1.68 yrs, height: 174.85 ± 6.10 cm, weight: 68.15 ± 9.83 kg) and 15 female subjects (age: 21.17 ± 1.58 yrs, height: 168.20 ± 5.55 cm, weight: 55.73 ± 6.94 kg) participated in this study. The study used wireless three channel EMG. Results: In this study, there was no gender difference in quadriceps femoris activity during the US and DS periods, and there was no significant difference between the male group before and after postural maintenance during the US and DS periods. The quadriceps muscle of the female group also did not show a significant difference before and after US sitting. However, the vastus medialis muscle activity during DS in the female group was significantly lower after application than before application of maintaining a sitting posture (p<.05). There was no interaction effect between the 15-minute sitting position application and gender. Conclusion: Our results demonstrate that sitting in a chair affects the transient functioning of the quadriceps muscle in women. Therefore, emphasize the need for active rest when sitting in a chair for long periods of time.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.519-524
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• 2023

The purpose of this study is to construct basic data for efficient technical training by investigating the difference in muscle activity during badminton technical movements involving jump motions similar to game situations. Seven male badminton players were randomly assigned to perform smash, drop, and clear techniques, and electromyograms were measured during the implementation of three technical movements. Measured EMG was calculated by RMS and one-way ANOVA was performed. The muscle activity of the smashing motion did not show any significant difference according to the site. In drop motion, activity of PM in the upper extremity muscles was lower than that of BC and ECR, and FCR activity was lower than that of EC. The activity of ECR was higher than that of PM and FCR. The activity of ES in trunk muscles was lower than that of RF and GM. RF activity of lower extremity muscles was higher than that of ES and BF. In clear motion, the activity of TC in upper extremity muscle was higher than FCR. The activity of ES in trunk muscles was lower than that of BF. RF activity of lower extremity muscles was higher than that of BF, and BF activity was lower than that of RF and GM. The activity of GM was higher than that of BF. As for muscle activity according to badminton skills, smash and drop motions were higher than clear motions in FCR, and clear motions were higher than smash and drop motions in RA. In conclusion, it is considered that muscle activity during the badminton game is different according to the characteristics of each skill, and FCR can affect the smash and drop, and RA can affect the clear motion.