• Physical Therapy Rehabilitation Science
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• v.10 no.1
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• pp.10-15
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• 2021

Objective: Limited ankle dorsiflexion is related to ankle injuries. There are various exercises to increase the flexibility of the gastrocnemius for improving the passive range of motion in ankle dorsiflexion. However, to performances in daily activities and athletic sports and higher efficiency of walking and running, both ankle dorsiflexion passive and active range of motion are needed. To investigate the effects of combined gastrocnemius stretching and tibialis anterior resistance exercise on ankle kinematics (passive and active range of motion of ankle dorsiflexion) and tibialis anterior muscle activity in subjects with limited ankle dorsiflexion. Design: Cross-sectional single-group repeated measures design. Methods: Fourteen subjects with limited ankle dorsiflexion were recruited (in the right ankle in 7 and the left ankle in 7). All subjects performed gastrocnemius stretching alone and tibialis anterior resistance exercise after gastrocnemius stretching. The passive and active range of motion of ankle dorsiflexion were measured after interventions immediately. The tibialis anterior activity was measured during active range of motion of ankle dorsiflexion measurement. Results: There was no significant difference of ankle dorsiflexion passive range of motion between gastrocnemius stretching alone and the tibialis anterior resistance exercise after gastrocnemius stretching. The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased active range of motion of ankle dorsiflexion compared to gastrocnemius stretching alone (p<0.05). The tibialis anterior resistance exercise after gastrocnemius stretching significantly increased tibialis anterior activity better than did gastrocnemius stretching alone. Conclusions: Thus, subjects with limited ankle dorsiflexion should be encouraged to perform tibialis anterior resistance exercises.

• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.155-165
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• 2005

The purpose of this study was to compare the muscle activities of Double Legged Jump (DLJ) and Single Legged Jump (SLJ) by the normalization of muscle activity. Eight college students without the lower extremity injuries were selected as subjects for collecting EMG data of vastus medialis and gastrocnemius. The entire section of motion was established as eccentric and concentric contractions, and each of the contractions was divided into three sections with equal timing intervals, which becomes a total of 6 phases. The EMG data of each phase was integrated and normalized. The muscle activities of the vastus medialis for both eccentric and concentric contractions were significantly different between DLJ and SLJ(p<.05). The increase in overall muscle activity of SLJ was 33.6%. Approximately, there was an increase of 25.9% in eccentric contraction and 40% in concentric contraction. Moreover, the data of the muscle activity of gastrocnemius was similar to the data of the muscle activity of vastus medialis. In conclusion, this research suggests muscle activity of a certain motion can be normalized for an analysis of another motion.

• 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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.71-78
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• 2015

In order to deduce an objective evaluation method of motion seasickness incidence (MSI) by ship motions during underway in irregular waves and to present the fundamental data of passenger comfort on the yacht and the passenger ship according to the result, the MSI of the trainees by the questionnaires was analysed and compared with the rate of variation of salivary ${\alpha}$-amylase activity (VSAA) on the training ship "A-ra ho" of Jeju national university. Relationship between rate of variation (x) by salivary ${\alpha}$-amylase activity and motion seasickness incidence (y) was described by the equation, MSI(%) = 0.6073 x + 12.189 including the correlation coefficient ($R^2=0.9853$). The result obtained through the rate of variation of salivary ${\alpha}$-amylase activity which was the quantitative evaluation method for ship motions causing seasickness was most affected by z-vertical acceleration and occurred within the frequency range 0.1 to 0.3Hz centered on 0.2Hz, and the simulation result based on this finding showed the motion seasickness rate at approximately 4% lower than the rate obtained through the survey.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.2
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• pp.23-29
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• 2012

Purpose : Purpose of this study was to investigate whether cervicothoracic posture was associated with scapula orientation and muscle activity during shoulder abduction. Methods : Cervicothoracic junction angle and thoracic kyphosis angle were measured in health twenty subjects. Then, scapular resting orientation and range of motion (upward/downward rotation, internal/external rotation) and muscle activity (upper trapezius, lower trapezius, serratus anterior) was determined using motion capture system and surface electromyography while subjects performed shoulder abduction. Results : Cervicothoracic junction angle was significantly associated with range of motion of scapular internal/external rotation during shoulder abduction. Thoracic kyphosis angle was significantly associated with scapular resting orientation of upward/downward rotation and average IEMG of lower trapezius. Conclusion : The result of this study shows that poor cervicothoracic posture is relationship with altered scapular kinematics cause of shoulder dysfunction. These findings suggested that cervicothoracic posture may be considered in occupation and exercise including arm elevation over head as well as used as predict factor to estimate shoulder dysfunction.

• Design Convergence Study
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• v.14 no.5
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• pp.157-169
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• 2015

In this study, three axillary crutches(Mobilegs, KM crutch, Pro In-motion) were tested with 12 healthy male subjects by measuring the EMG activity of the latissimus dorsi and gastrocnemius and the user-perceived levels focusing on the comfort and ease of use. The result showed that the EMG activity of the gastrocnemius was significantly reduced during ambulation using Mobilegs and Pro In-motion compared with the ambulation using KM crutch, a conventional crutch. However, no statistically significant difference was found for EMG activity of the latissimus dorsi. Subjects perceived the Mobilegs to be more comfortable and easy to use than the other crutches. Theses result may delivered mostly from the characteristics of spring-loaded axillary pad and ergonomic crutch handle. The results indicate that ambulation using the spring-loaded crutch is much easy with asking less exertion at gastrocnemius. In addition, the characteristics of crutch design, such as embedded spring, makes muscles to consume less energy. When the reasonable structure and form of the axillary pad and crutch handle are applied herein, the ambulation using the crutches are perceived to comfort.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1361-1369
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• 1996

Motion estimation is one of the key components for high quality video coding. In this paper, a new motion estimation scheme for MPEG-like video coder is suggested. The proposed temporally adaptive motion estimation scheme consists of five functional blocks: Temporal subband analysis (TSBA), extraction of temporal information, scene change detection (SCD), picture type replacement (PTR), and temporally adapted block matching algorithm (TABMA). Here all the functional components are based on the temporal subband analysis. In this papre, we applied the analysis part of subband decompostion to the temporal axis of moving picture sequence, newly defined the temporal activity distribution (TAD) and average TAD, and proposed the temporally adapted block matching algorithm, the scene change detection algorithm and picture type replacement algorithm which employed the results of the temporal subband analysis. A new block matching algorithm TABMA is capable of controlling the block matching area. According to the temporal activity distribution of objects, it allocates the search areas nonuniformly. The proposed SCD and PTR can prevent unavailable motion prediction for abrupt scene changes. Computer simulation results show that the proposed motion estimation scheme improve the quality of reconstructed sequence and reduces the number of block matching trials to 40% of the numbers of trials in conventional methods. The TSBA based scene change detection algorithm can detect the abruptly changed scenes in the intentionally combined sequence of this experiment without additional computations.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.2-9
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• 2000

This paper presents a statistical motion activity description method and video retrievals by using the intensity and directions of the extracted motion vectors from video sequence. Since the proposed method can represent temporal and spatial cognitive characteristics of an entire video, several images between key frames, and images in a certain interval, it can be effectively applied to digital video services such as video retrieval, surveilance, multimedia database, and broadcasting filterings. In the paper, the effectiveness of the proposed algorithm is shown with a lot of shots of MPEG-7 video dataset.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2C
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• pp.193-200
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• 2003

In this paper, we propose a motion estimation method using hierarchical triangulation that changes the triangular mesh structure according to it's motion activity. The subdivision of triangular mesh is performed from the amount of motion that is calculated from the variance of image difference. As a result, node distribution is concentrated on the region of high activity. The subdivision method that makes it possible to yield hierarchical triangular mesh is proposed as well as the additional information reduction coding method for hierarchical mesh structure is described. By the simulation, proposed method have better performance than the conventional BMA(Block Match Algorithm) and the other mesh based method.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.23-32
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• 2017

PURPOSE: Flexibility and range of motion are very important factors in sports performance, rehabilitation, and musculoskeletal pain. The purpose of this study was to measure the effects of cupping therapy on flexibility, muscle activity, and pain threshold of hamstring muscle compared to passive stretching in healthy subjects. METHODS: Thirty healthy subjects were randomly assigned in a crossover design to cupping therapy and passive stretching. Subjects were tested to compare their effects according to the intervention such as Passive range of motion (PROM) (straight leg raising) and active range of motion (AROM). And algometer (pain) testing and MVC assessment using EMG were performed as dependent variables. RESULTS: The cupping therapy group and passive stretching group showed significant differences in all variables including PROM (p=.00, p=.00), AROM (p=.00, p=.03), Pain Threshold (p=.03, p=.08), Semitendinosus MVC (p=.01, p=.00), and Biceps femoris MVC (p=.01, p=.16). There were no significant differences between the two groups in all variables. CONCLUSION: These findings of this study suggested that cupping therapy has as much positive effect on flexibility, pain threshold, and muscle contraction as passive stretching. Also, it is more convenient and easier to work on patients than passive stretching. Therefore, cupping therapy should be considered as another option to treat range of motion, pain, and muscle activity in the clinical field.