• 한국운동역학회지
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• 제15권2호
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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 Korean Physical Therapy
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• 제28권6호
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• pp.349-354
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• 2016

Purpose: The purpose of the study was to investigate the thickness of deep neck flexors (DNF) and sternocleidomastoid muscle (SCM) bilaterally during deep neck flexor endurance test using ultrasonography images. Methods: Healthy volunteers (n=22), 20-25 (mean 22.2) years old, were recruited for the study. Participants were asked to perform the craniocervical flexion test (CCFT) in a seated position to measure deep neck flexor endurance. The thickness of DNF and SCM was assessed bilaterally and was measured using ultrasonography images at resting, contracted, pre-terminal and terminal phases of the neck muscle endurance test. Muscle contraction pattern was also observed along with the changes in muscle thickness from the resting phase to the terminal phase. Repeated-measure ANOVA was employed to compare muscle thickness bilaterally at each phase. Results: The thickness of right and left muscles was found to be significantly different in DNF both at resting and contracted phases (p=0.02, p<0.01, respectively), whereas no significant difference was observed in SCM at resting or contracted phases (p=0.59, p=0.18, respectively). Thickness changes from resting to contracted phase were not significantly different both in DNF and SCM (p=0.18, p=0.22, respectively). Muscle contraction patterns in right and left muscles were shown to be similar. Conclusion: The current study, performed on (with) healthy subjects, significantly detected different right and left muscle thickness in DNF, but the muscle contraction patterns were similar in DNF and SCM bilaterally. Further study is required to investigate DNF and SCM muscle size and function in people with neck pain.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.244-250
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• 2021

Objective: The purpose of this study was to investigate the effect of sprinter pattern bridging exercise using theraband on activation of lower extremity and abdominal muscle and to find out postures that can effectively improve abdominal and lower extremity muscle strength and increase abdominal stability. Methods: This study was designed as a cross-sectional study. The following research was done with applicants attending S university in Seoul to compare the difference in muscle activity between one-leg-Support bridging exercise and sprinter-pattern bridging exercise using theraband. For 48 study participants, we first measured their MVC. Then, we applied one-leg-support bridging exercise and sprinter-pattern bridging exercise at random order. These data were expressed as the percentage of maximal voluntary contraction (%MVC).Electromyography analysis was performed by measuring the external obliques, internal obliques, biceps femoris, and gluteus maximus. Results: There was a statistically significant increment of muscle activity in external and internal oblique muscle(p<0.001)by sprinter-pattern bridging exercise using theraband. On the lower body, statistically significant increment of muscle activity in biceps femoris and gluteus maximus was found(p<0.05). On the other hand, on erector spinae, there was statistically significant decrease in muscle activity(p<0.05). Conclusions: Efficient treatment is expected when sprinter-pattern bridging exercise using theraband is applied clinically.For patients with chronic knee and ankle pain who have difficulty bearing weight, including low back pain and internal rotation of the femur, starting with a low weight bearing, we think it will be helpful in planning systematic training aimed at progressively strengthening the lower extremities.

• PNF and Movement
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• 제18권1호
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• pp.35-44
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• 2020

Purpose: The purpose of this study was to investigate the effect of the simultaneous abdominal drawing-in maneuver (ADIM) on the muscle activity of the ipsilateral trunk and leg during proprioceptive neuromuscular facilitation (PNF) leg flexion, adduction, and external rotation with knee flexion (D1) patterns. Methods: The participants were 20 healthy adult males and females (18 males and 2 females). The maneuvers were performed by a physical therapist who fully understands the PNF leg patterns (D1) and their application in clinical practice. The participants were trained and allowed to practice for 15 minutes prior to applying ADIM, to ensure adequate learning as evidenced by the pressure biofeedback unit. In this study, we measured the muscle activity of the trunk and leg when the PNF leg pattern (D1) was performed by the physical therapist either sustaining or releasing the ADIM. Muscle activity was measured on the right transverse abdominis muscle (TRA), the external abdominal oblique muscle (EO), the internal abdominal oblique muscle (IO), the erector spinae muscle (ES), the vastus medialis oblique muscle (VMO), the vastus lateralis oblique muscle (VLO), and the tibialis anterior muscle (TA) and compared using the mean values from averaging three repeated measurements. Results: The muscle activity of the transversus abdominis, the external abdominal oblique, the internal abdominal oblique, the vastus medialis oblique, and the vastus lateralis oblique was significantly greater (p < 0.05), and the muscle activity of the erector spinae was significantly less (p < 0.05) during PNF leg pattern (D1) when the ADIM contraction was sustained compared to when it was not. Conclusion: These results suggest that sustaining ADIM during PNF leg pattern (D1) training increases the trunk and leg muscle activity, resulting in more effective training.

• PNF and Movement
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• 제22권1호
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• pp.151-158
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• 2024

Purpose: The present study investigated how variations in diagonal exercises affect shoulder muscle activity, examining changes in neuromuscular activation during scapular and shoulder diagonal patterns of exercises. Furthermore, we explored whether the exercise phase affects muscle activation. Methods: Sixteen asymptomatic male participants were recruited. Four diagonal pattern exercises (scapular anterior elevation, posterior elevation, flexion-adduction-external rotation, flexion, abduction-external rotation), and two exercise phases (concentric and eccentric) were administered. Surface electromyography data were collected. Results: Upper trapezius activity was significantly higher during the concentric phase of scapular posterior elevation exercises compared with the others (p<0.05). The serratus anterior, anterior deltoid, and infraspinatus activities were significantly higher during shoulder diagonal pattern exercises compared with the scapular diagonal pattern exercises (p<0.05). Except for the lower trapezius, muscular activities during the concentric phase were significantly greater compared with the eccentric phase (p<0.05). Conclusion: The current study suggests that the diagonal pattern of exercise may contribute to selective strengthening of the shoulder complex muscles and that the form of exercise should be tailored to the subject. It also suggests that diagonal exercises with concentric contractions tend to be more beneficial than eccentric contractions for overall muscle recruitment, but the effects vary for specific diagonal patterns.

• 대한산업공학회지
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• 제19권4호
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• pp.87-96
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• 1993

Spectrum analysis of surface electromyogram (FMG) signals is an effective approach to the study of localized muscular fatigue during isometric contraction. Many investigators have con firmed the frequency of the EMG signals being lowered during sustained contaction. In this study, the cyclic loading tasks were performed, and a comparison was made for the median power frequency shift pattern of the EMG signals with the sustained contraction of the same load. The median power frequency shift of the EMG signals for the cyclic loading task was found to be a part of that for the sustained contraction. Based on this result, a new muscle fatigue index was computed by normalizing the duration of the sustained contraction. A fatigue index was obtained as a function of exertion level and the work/rest schedule. With the proposed fatigue index, it is possible to evaluate or predict the degree of muscular fatigue for a physically demanding task.

• The Journal of Korean Physical Therapy
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• 제11권1호
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• pp.137-141
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• 1999

Proprioceptive neuromuscular facilitation(PNF), pelvic patterns are very important for orthopaedic and neurologic patient. It is an essential treatment techniques for motor developmental disorder. CVA, lumbar disk, muscle weekness and pain control of lumbar, pelvic and lower extremity, Pelvic patterns of PNP has 4 different type of basic pattern. each of them is combinding of movement plane and functional movement. Biomechanically most of PNF patterns are a concentric contraction with third-class lever. But the movement pattern have a technique of combination of isotonic that should make a eccentric contraction with second-class lever.

• 대한인간공학회지
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• 제14권1호
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• pp.9-23
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• 1995

The objectives of the study were twofole: (1) to investigate effects of rhythmic contraction and sustained contraction methods on recovery rate of isometric endurance capacity and (2) to compare aptterns of muscle recruitment of both arms observed during each contraction period. In the experiment, each of two subjects performed five successive rhythmic or sustained isometric contractions at 50% MVC with both arms to the point of fatigue, which was the failure to maintain the required tension. In making the contractions, the subjects stood erect with upper arms held at an angle of approximately 90 .deg. to the forearm. The interval between the successive contractions was kept constant at 3, 7, 20, or 40 minutes. Regardless of the contraction methods, the recovery rate was least at the shortest interval and was highest at the longest interval. However, a statistical analysis showed that the recovery rates for the rhythmic contractions were significantly lower than those for the sustained contractions throughout 4 different intervals. Furthermore, as the frequency of the rhythmic contractions per min, increased 4 to 6 times, the recovery rate of isometric endurance capacity decreased. From an EMG anglysis, recruitment pattern of the muscules of both arms was found to be common between two different contraction methods. The biceps muxcles of the upper arms played a major role in exerting 50% MVC, while the brachioradialis muscles of the forearms acted as synergists. As the contraction proceeded, the role of the biceps muscles as a prime mover lessened due to the fatigue. Then, the brachioradialis muscles exerted more strength to sustain 50% MVC. The implications of these finding were discussed.

• 대한인간공학회지
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• 제30권6호
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• pp.689-694
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• 2011

Objective: The aim of this study is to evaluate the fluctuation of signal amplitude during repetitive dynamic contraction based on surface electromyography(EMG). Background: The most previous studies were considered isometric muscle contraction and they were difference to smoothing window length by moving average filter. In practical, the human movement is dynamic state. Dynamic EMG signal which indicated as the nonstationary pattern should be analyzed differently compared with the static EMG signal. Method: Ten male subjects participated in this experiment, and EMG signal was recorded by biceps brachii, anterior/posterior deltoid, and upper/lower trapezius muscles. The subject was performed to repetitive right horizontal lifting task during ten cycles. This study was considered three independent variables(muscle, amplitude processing technique, and smoothing window length) as the within-subject experimental design. This study was estimated muscular activation by means of the linear envelope technique(LE). The dependent variable was set coefficient of variation(CV) of LE for each cycle. Results: The ANOVA results showed that the main and interaction effects between the amplitude processing technique and smoothing window length were significant difference. The CV value of peak LE was higher than mean LE. According to increase the smoothing window length, this study shows that the CV trend of peak LE was decreased. However, the CV of mean LE was analyzed constant fluctuation trend regardless of the smoothing window length. Conclusion: Based on these results, we expected that using the mean LE and 300ms window length increased reproducibility and signal noise ratio during repetitive dynamic muscle contraction. Application: These results can be used to provide fundamental information for repetitive dynamic EMG signal processing.

• 한국전문물리치료학회지
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• 제29권3호
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• pp.187-193
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• 2022

Background: Neuromuscular electrical stimulation (NMES) is a physical modality used to activate skeletal muscles for strengthening. While voluntary muscle contraction (VMC) follows the progressive recruitment of motor units in order of size from small to large, NMES-induced muscle contraction occurs in a nonselective and synchronous pattern. Therefore, the outcome of muscle strengthening training using NMES-induced versus voluntary contraction might be different, which might affect balance performance. Objects: We examined how the NMES training affected balance and proprioception. Methods: Forty-four young adults were randomly assigned to NMES and VMC group. All participants performed one-leg standing on a force plate and sat on the Biodex (Biodex R Corp.) to measure balance and ankle proprioception, respectively. All measures were conducted before and after a training session. In NMES group, electric pads were placed on the tibialis anterior, gastrocnemius, and soleus muscles for 20 minutes. In VMC group, co-contraction of the three muscles was conducted. Outcome variables included mean distance, root mean square distance, total excursion, mean velocity, 95% confidence circle area acquired from the center of pressure data, and absolute error of dorsi/plantarflexion. Results: None of outcome variables were associated with group (p > 0.35). However, all but plantarflexion error was associated with time (p < 0.02), and the area and mean velocity were 37.0% and 18.6% lower in post than pre in NMES group, respectively, and 48.9% and 16.7% lower in post than pre in VMC group, respectively. Conclusion: Despite different physiology underlying the NMES-induced versus VMC, both training methods improved balance and ankle joint proprioception.