• The Korean Journal of Physiology and Pharmacology
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• 제13권5호
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• pp.393-400
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• 2009

NO released by myenteric neurons controls the off contraction induced by electrical field stimulation (EFS) in distal esophageal smooth muscle, but in the presence of nitric oxide synthase (NOS) inhibitor, L-NAME, contraction by EFS occurs at the same time. The authors investigated the intracellular signaling pathways related with G protein and ionic channel EFS-induced contraction using cat esophageal muscles. EFS-induced contractions were significantly suppressed by tetrodotoxin ($1\;{\mu}M$) and atropine ($1\;{\mu}M$). Furthermore, nimodipine inhibited both on and off contractions by EFS in a concentration dependent meaner. The characteristics of 'on' and 'off contraction and the effects of G-proteins, phospholipase, and $K^+$ channel on EFS-induced contraction in smooth muscle were also investigated. Pertussis toxin (PTX, a $G_i$ inactivator) attenuated both EFS-induced contractions. Cholera toxin (CTX, $G_s$ inactivator) also decreased the amplitudes of EFS-induced off and on contractions. However, phospholipase inhibitors did not affect these contractions. Pinacidil (a $K^+$ channel opener) decreased these contractions, and tetraethylammonium (TEA, ${K^+}_{Ca}$ channel blocker) increased them. These results suggest that EFS-induced on and off contractions can be mediated by the activations Gi or Gs proteins, and that L-type $Ca^{2+}$ channel may be activated by G-protein ${\alpha}$ subunits. Furthermore, ${K^+}_{Ca^-}$ channel involve in the depolarization of esophageal smooth muscle. Further studies are required to characterize the physiological regulation of $Ca^{2+}$ channel and to investigate the effects of other $K^+$ channels on EFS-induced on and off contractions.

• Physical Therapy Rehabilitation Science
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• 제11권2호
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• pp.245-252
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• 2022

Objective: This study aimed to investigate the abdominal muscle activity difference while performing the abdominal bracing technique focusing on inspiration (abdominal bracing group), the general abdominal bracing technique (general bracing group), and the abdominal hollowing technique (abdominal hallowing group) Design: A cross-sectional study design. Methods: Thirty-three healthy participants were recruited for this study. The participants were allocated to 3 different groups; Abdominal bracing group, general bracing group, and abdominal hallowing group. The surface electromyography was placed over the rectus abdominis, external oblique, and internal oblique muscles to collect the activation of abdominal muscles during the trial. Results: The muscle activity of the abdominal bracing group and general bracing groups was significantly higher in all abdominal muscles than in the abdominal hollowing group (p<0.05) Both rectus abdominis and external oblique muscles showed higher muscle activations in the abdominal bracing group over the general bracing group (p<0.05). However, the ratio of bilateral external obliques and rectus abdominis to bilateral internal obliques was highest when the hollowing technique was applied (p<0.05). Conclusions: The results of study showed the abdominal bracing technique that emphasized inhalation rather than the abdominal hollowing technique or general abdominal bracing technique increased the activity of the abdominal muscles. Therefore, this study is considered to be a data for effective training if the abdominal bracing technique that emphasizes inhalation is applied as a method to increase the activation of the abdominal muscles.

• 한국운동역학회지
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• 제32권3호
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• pp.80-86
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• 2022

Objective: The purpose of this study was to investigate the effects of three rotational jump conditions (standing jump, left rotational jump and right rotational jump) on stability through center of pressure (COP) and EMG variables analysis. Method: A total of 16 college students (age: 24.13 ± 7.17 years, height: 169.24 ± 8.23 cm, weight: 65.65 ± 13.88 kg) participated in this study. The study used wireless two COP plates and wireless eight channel EMG. The analyized variables were 11 variables for COP and RMS for EMG, which were analyzed using one-way analysis of variance with repeated measures according to three rotational jump conditions. Results: Among the COP variables, left rotational jump (LRJ) and right rotational jump (RRJ) were larger than standing jump (SJ) for left and right amplitude, area, total displacement, and average velocity for both feet among the variables of COP, and for area of the left foot, RRJ was larger than that of SJ. Among the EMG variables, there was no statistical difference between the muscle activations, but the muscle activity was significantly higher in the order of RRJ, LRJ, and SJ according to direction of rotation. Conclusion: Although the results of COP and EMG were not consistent through this study, it can be expected that the differences in COP was due to the amount of rotation during rotational jump-landing in the left and right directions, and that the EMG is determined by the lateral movements required for rotation.

• The Journal of Korean Physical Therapy
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• 제25권3호
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• pp.143-148
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• 2013

Purpose: The purpose of this study was to investigate whether changes in electromyography (EMG) activations of spinal stability muscles with respiratory demand change were due to changes in respiratory demand or in postural demand. Methods: Forty healthy subjects (19male, 21female, $20.8{\pm}1.9$years old) performed quiet breathing and four different forced respiratory maneuvers (FRM) (Pulsed Lip Breathing, Diaphragmatic Breathing, Combination breathing, and respiratory muscle endurance training breathing) while in sitting and standing positions. EMG data for four muscles (TrA/IO, EO, RA, and ES) were collected and filtered using a band pass filter (20~200Hz) and a notch filter (60, 120, 180Hz). Results: There were no significant differences on percentage of change on %MVIC between QB and FRM (PLB, CB, DB, and RMET) between positions (all p>0.05).

• 대한정형도수물리치료학회지
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• 제16권1호
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• pp.9-19
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• 2010

Purpose : To identify whether isometric shoulder horizontal extension (ISHE) exercise could sufficiently activate the lumbar multifidus muscle, and to determine appropriate exercise intensity to increase muscle strength. Methods : Twenty healthy volunteers (10 males and 10 females) participated in this study. ISHE exercises on the dominant side were performed with $90^{\circ}$ shoulder abduction held in $90^{\circ}$ elbow flexion so that their arms were in the horizontal plane. Electromyographic (EMG) measurements of multifidus activation were performed in standing and supine positions, and were taken under four strength conditions: 75%, 50% and 25% of maximum shoulder horizontal extension strength, and maximum strength. Results : The EMG activations of both lumbar multifidus increased significantly with ISHE exercises of larger % strength (p<.05). In their multifidus EMG data measured in standing and supine positions, men differed significantly in their 75%, 50% and 25% strength for both sides (p<.05), and women differed significantly in their 75%, 50% and 25% strength on their 5th lumbar vertebrae's left side, but 75% only for their 5th lumbar vertebrae's right side (p<.05). The EMG data of 5th lumbar vertebrae's left and 5th lumbar vertebrae's right sides appeared to differ significantly at all strength levels for men while standing, but only at the 25% level for women in the supine position (p<.05). These findings indicate that ISHE exercises can be considered a beneficial method to enhance the multifidus strength. Conclusion : This study provides useful information for further study in this field.

• 한국운동역학회지
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• 제25권3호
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• pp.323-333
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• 2015

Objective : The purpose of this study was to investigate the changes of gait patterns and muscle activations with increased loads during stair walking. Also, it can be used as descriptive data about continuous stair walking in a real life setting. Method : Twelve sedentary young male adults(Age: $27.0{\pm}1.8yrs$, Weight: $65.8{\pm}9.9kg$) without any lower extremity injuries participated in this study. Participants performed stair walking up 7 floors and their ascending and descending motion on each floor was analyzed. A wireless electromyography(EMG) were attached on the Rectus Femoris(RF), Biceps Femoris(BF), Gastrocnemius(GN), Tibialis Anterior(TA) muscle to calculate integrated EMG(iEMG), median frequency(MDF) and co-contraction index(CI). Chest and left heel accelerometer signal were recorded by wireless accelerometer and those were used to calculate approximate entropy(ApEn) for analyzing gait pattern. All analyses were performed with SPSS 21.0 and for repeated measured ANOVA and Post-hoc was LSD. Results : During ascending stairs, there were a statistically significant difference in Walking time between 1-2nd and other floors(p=.000), GN iEMG between 2-3th and 6-7th(p=.043) floor, TA MDF between 1-2nd and 5-6th(p=.030), 6-7th(p=.015) floor and TA/GN CI between 2-3th and 6-7th(p=.038) floor and ApEn between 1-2nd and 6-7th(x: p=.003, y: p=.005, z: p=.006) floor. During descending stairs, there were a statistically significant difference in TA iEMG between the 6-5th and 3-2nd(p=.026) floor, and for the ApEn between the 1-2nd and 6-7th(x: p=.037, y: p=.000, z: p=.000) floor. Conclusion : Subjects showed more regular pattern and muscle activation response caused by regularity during ascending stairs. Regularity during the first part of stair-descending could be a sign of adaptation; however, complexity during the second part could be a strategy to decrease the impact.

• 대한물리의학회지
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• 제8권4호
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• pp.497-503
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• 2013

PURPOSE: The purpose of this study was to investigate the change of triceps surae activation during heel raise test in standing among knee flexion angles($0^{\circ}C$, $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$). METHODS: Twenty healthy individuals performed unilateral plantarflexion in standing with $0^{\circ}C$, $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$ knee flexion. Activity of medial gastrocnemius(MG), lateral gastrocnemius(LG), soleus(Sol) was recorded with surface electromyography(EMG). RESULT: The muscle activations induced the four different positions were compared and results showed that was significant difference MG and LG while the angle increase from $0^{\circ}C$ to $30^{\circ}C$, $45^{\circ}C$, $60^{\circ}C$ but Sol did not show significant differences in every angle. CONCLUSION: This study suggest that $30^{\circ}C$ knee flexion is required to induce a significant mechanical disadvantage of gastrocnemius.

• 대한의용생체공학회:의공학회지
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• 제24권5호
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• pp.435-442
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• 2003

In this paper, biomechanical aspects of dynamic대학교postural responses against forward perturbations were experimentally determined simultaneous measurements of joint angles, accelerations. EMG activations, center of pressure(CoP) movements and ground reaction forces(GRF), Thirteen young healthy volunteers, stood on a flat platform, were translated into the forward direction by an AC servo-motor at two separate velocities(0.1m and 0.2m/s). In order to recover postural balance against the forward perturbation, joint motions were observed in the sequence of the ankle dorsiflexion, the knee flexion and then the hip flexion during the later acceleration phase. Both acceleration patterns at the heel and the sacrum were shown the forward acceleration pattern during the later acceleration phase and early of constant velocity phase as increasing platform velocity, respectively. Tibialis anterior(TA) for the ankle dorsiflexion and biceps femoris(BF) for the knee flexion. the primary muscle to recover the forward perturbation, was activated during the half of acceleration phase. Ankle strategy was used for slow-velocity perturbation, but mixed strategy of both ankle and hip used for the fast-velocity perturbation. In addition, parameters of perturbation such as timing and magnitude influenced the postural response against the perturbation.

• Journal of Ginseng Research
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• 제30권2호
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• pp.57-63
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• 2006

One of the various signaling agents in the animal cells is the simple ion called calcium, $Ca^{2+}$.$Ca^{2+}$ controls almost everything that animals do, including fertilization, secretion, metabolism, muscle contractions, heartbeat, learning, memory stores, and more. To do all of this, $Ca^{2+}$ acts as an intracellular messenger, relaying information within cells to regulate their activity. In contrast, the maintenance of intracellular high $Ca^{2+}$ concentrations caused by various excitatory agents or toxins can lead to the disintegration of cells (necrosis) through the activity of $Ca^{2+}$-sensitive protein-digesting enzymes. High concentrations of calcium have also been implicated in the more orderly programs of cell death known as apoptosis. Because this simple ion, acts as an agent for cell birth, life and death, to coordinate all of these functions, $Ca^{2+}$ signalings should be regulated precisely and tightly. Recent reports have shown that ginsenosides regulate directly and indirectly intracellular $Ca^{2+}$ level with differential manners between neuronal and non-neuronal cells. This brief review will attempt to survey how ginsenosides differentially regulate intracellular $Ca^{2+}$ signaling mediated by various ion channels and receptor activations in neuronal and non-neuronal cells.

• 한국운동역학회지
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• 제33권4호
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• pp.128-136
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• 2023

Objective: The aim of this study was to investigate the effect of an 8-week closed kinetic chain typed Reformer and Chair Pilates exercise on static and dynamic lower limb alignment for healthy female adults. Method: Ten healthy young female adults without musculoskeletal injury history in last 6 months (Age: 29.3 ± 3.5 yrs., Height: 165 ± 3.4 cm, Body mass: 58.2 ± 5.4 kg) participated in this study. All participants asked to join the 8-week closed kinetic chain typed Reformer and Chair Pilates exercise, and the program was conducted for 60 minutes twice a week. Participants were asked to be measure a static Q-angle and performed free squat one week before and after the program. A 3-D motion analysis with 8 infrared cameras and 5 channels of EMG was executed in this study. The effectiveness of the training was evaluated by paired t-test, and the significance level was set at .05. Results: A significantly decreased in internal rotation angles was found at hip joint during free squat after the training. Also, significantly decreased in lateral rotation angles were found at knee and ankle joint during free squat after training. Finally, significantly decreased in muscle activations were found at adductor longus and peroneus longus during free squat after training. Conclusion: From results of our study, it is concluded that an 8-week closed kinetic chain typed Pilates exercise positively effect on lower limb alignment during dynamic movement.