• Physical Therapy Rehabilitation Science
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• v.7 no.2
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• pp.72-77
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• 2018

Objective: This study aimed to compare the effects of core exercise methods on muscle activation and muscle thickness in healthy young adults and to propose effective core exercise methods. Design: Three-group pretest-posttest design. Methods: A total of 30 healthy young adults (14 males, 16 females) voluntarily participated in the study. Subjects were randomized to the prone plank exercise (n=10), reverse plank exercise (n=10), or bridge exercise (n=10) groups. Muscle activity and thickness of the rectus abdominis (RA), multifidus (MF), external oblique (EO), and internal oblique (IO) muscles were measured using surface electromyography and ultrasound. Subjects from each group participated in the exercises five times a week, with five 20-second sets during week 1. The set time was increased by 10 seconds per week. Results: Muscle activity and thickness in the prone plank, reverse plank, and bridge exercise group were statistically significant different for RA, MF, EO, and IO changes over time, and interaction between time and groups were also significantly different (p<0.05). We analyzed statistically significant differences between groups using a one-way analysis of variance for each period. A significant difference was observed after 4 weeks of exercise (p<0.05). Conclusions: The results suggest that the prone plank exercise is a beneficial method for enhancing muscle activation and thickness of the RA, EO, and IO compared to the reverse plank and bridge exercises. On the other hand, the reverse plank and bridge exercises are effective methods for enhancing the MF compared to the prone plank exercise.

• Journal of the Korean Applied Science and Technology
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• v.39 no.2
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• pp.335-339
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• 2022

The purpose of this research was to investigate the comparison of core muscle activities according to different performance in static Plank exercise. Ten "J" University's males(age, 23.20±0.65 years; height, 174.54±1.51 cm; body mass, 70.00±2.24 kg; and BMI, 22.94±0.51 kg/m²) completed this study as the subjects. Four type's static Plank motions were performed(full Plank, FP; elbow Plank, EP; side Plank, SP; reverse Plank, RP). For the EMG analysis, we measured the core muscle activities of right side on the rectus abdominis(RA), external oblique(EO), latissimus dorsi(LD), and erector spinae(ES). This research's results were as follows. LD and ES muscle activities were greatest during RP(p<.001). RA and EO muscle activities were greatest during EP(p<.001). Therefore, this results are anticipated to serve as basic data for static Plank performance applications in effective exercise programs.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.758-765
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• 2019

The purpose of the this study was to determine the comparative analysis of body muscle activities in plank exercise with and without thera-band. Twelve healthy adult males(age, $21.75{\pm}.57$ years; height, $173.33{\pm}1.34cm$; body mass, $65.92{\pm}1.64kg$; and BMI, $21.93{\pm}.46kg/m^2$) participated in this study as subjects. Plank exercises(full, elbow, side, and reverse plank) were performed with four different thera-band in without(WT), red color(RT), blue color(BT), and siver color(ST). We measured the muscle activities of the erector spinae(ES), deltoideus p. acromialis(DA), external oblique(EO), rectus abdominis(RA), rectus femoris(RF), latissimus dorsi(LD), pectoralis major(PM), and biceps femoris(BF). The research findings were as follows. ES and DA muscle activities were greatest during full plank performed with the WT(p<.05). EO, RA, RF, and PM muscle activities were greatest during full plank performed with the ST(p<.05). ES and DA muscle activities were greatest during elbow plank performed with the WT(p<.05). RF and PM muscle activities were greatest during elbow plank performed with the ST(p<.05). ES, EO, RA, RF, LD, PM, and BF muscle activities were greatest during side plank performed with the ST(p<.05). DA, EO, RA, RF, LD, PM, and BF muscle activities were greatest during reverse plank performed with the ST(p<.05). These results are expected to serve as reference materials for plank exercise applications in training programs for body muscle strengthening.

• Nuclear Engineering and Technology
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• v.47 no.7
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• pp.859-866
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• 2015

The aim of this work is to investigate the transport mechanism of radioactive nuclides through the reverse osmosis (RO) membrane and to estimate its effectiveness for nuclide separation from radioactive liquid waste. An analytical model is developed to simulate the RO separation, and a series of experiments are set up to confirm its estimated separation behavior. The model is based on the extended Nernst-Plank equation, which handles the convective flux, diffusive flux, and electromigration flux under electroneutrality and zero electric current conditions. The distribution coefficient which arises due to ion interactions with the membrane material and the electric potential jump at the membrane interface are included as boundary conditions in solving the equation. A high Peclet approximation is adopted to simplify the calculation, but the effect of concentration polarization is included for a more accurate prediction of separation. Cobalt and cesium are specifically selected for the experiments in order to check the separation mechanism from liquid waste composed of various radioactive nuclides and nonradioactive substances, and the results are compared with the estimated cobalt and cesium rejections of the RO membrane using the model. Experimental and calculated results are shown to be in excellent agreement. The proposed model will be very useful for the prediction of separation behavior of various radioactive nuclides by the RO membrane.

• Korean Journal of Applied Biomechanics
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• v.27 no.4
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• pp.247-255
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• 2017

Objective: The purpose of this study was to investigate the maximum core muscle activation angle according to core-strengthening exercises. Method: Twenty-six young female football players (age: $17.84{\pm}0.80years$, height: $163.08{\pm}5.25cm$, weight: $54.96{\pm}7.41kg$) registered in the Korea Football Association from D High School located in Seoul were the subjects of this research. An electromyogram (Noraxon, USA) was used for monitoring the maximum core muscle contraction activity. Results: The angle for the maximum core muscle strength per core exercise and muscle was the smallest for the upper rectus abdominis in the windshield wiper exercise. The angle of the vastus medialis was significantly the largest. The range of angles at which the maximum strength was observed for each core exercise were as follows: 1) abdominal flutter kicks ($11{\sim}40^{\circ}$), 2) leg raises ($21{\sim}34^{\circ}$), 3) scissors ($45{\sim}66^{\circ}$), 4) knee to elbow sit-ups ($42{\sim}64^{\circ}$), 5) reverse crunches ($9{\sim}40^{\circ}$), 6) butt-ups ($24{\sim}32^{\circ}$), 7) V sit-ups ($5{\sim}24^{\circ}$), 8) windshield wipers ($11{\sim}20^{\circ}$), 9) bird dog ($11{\sim}18^{\circ}$), and 10) raised leg plank ($38{\sim}50^{\circ}$). Conclusion: Four kinds of motion could be classified according to the range of angles at which the core muscles were maximally activated. The first group involves the range of motion that gives the maximum muscle strength when the lower extremity and ground angle was between $5^{\circ}$ and $24^{\circ}$, such as the V sit-ups, windshield wipers, and bird dog. The second group comprised the flutter kicks and reverse crunches at an angle between $9^{\circ}$ and $40^{\circ}$. The third group comprised the leg raise and butt-up exercises at an angle between $21^{\circ}$ and $34^{\circ}$. The fourth group included the scissors, knee to elbow sit-ups, and raised leg plank at an angle between $38^{\circ}$ and $66^{\circ}$. These results may be useful as basic data for core movement and core muscle training according to the purpose of exercise.