• Journal of Advanced Marine Engineering and Technology
• /
• 제22권4호
• /
• pp.429-435
• /
• 1998

Experiments were conducted to investigate the turbulent flow characteristics from on oblique impingement surface to an plane jet at the jet Reynolds number(Re based on the nozzle width) $3{\times}10^4$ The jet mean velocity and turbulent intensity profiles have been measured along the impingement surface by hot-wire anemometer. The nozzle-to-plate distance(H/B) ranged from 2 to 10 and the oblique angle (a) from 45 to 90 degree. Also the secondary peak of the turbulent intensity was observed at H/B=4 S/B 5 and a=90 degree. It has been found that the stagnation point shifted toward the minor flow region as the oblique angle decreased and the position of the stagnation point nearly coincided with that of the maximum turbulent intensity.

• Physical Therapy Rehabilitation Science
• /
• 제3권2호
• /
• pp.101-106
• /
• 2014

Objective: To investigate the appropriate position for abdominal drawing-in maneuver (ADIM) exercise by rehabilitative ultrasound image. Design: Cross-sectional study. Methods: Twenty-eight young adults with no history of low back pain participated in the study. Three positions compared were crook lying position with hip $60^{\circ}$ flexion, standing position with the feet hip width apart and knees straight, and saddle standing positionunsupported with the knees $20^{\circ}$ flexed. Once in the appropriate position, the subjects were verbally cued to draw in their abdominal wall, with the intention of pulling their navel inward toward their lower back. The thickness of each transversus abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles were measured via ultrasound and recorded at the end of inspiration. Results: When compared to the TrA thickness of rest, the TrA thickness was significantly increased in all three positions (crook lying, standing, and saddle standing) during the ADIM (p<0.05). IO thickness was significantly greater in standing and saddle standing than in crook lying (p<0.05). EO thickness was constant in all the three positions. Conclusions: The present study suggests that standing and saddle standing positions could be recommended for the ADIM to maximize recruitment of the TrA and IO activation. Specifically, the saddle standing position with knees flexed to $20^{\circ}$ was observed to increase the TrA activation more than the standing position. These findings should be considered when core stability exercises such as the ADIM are conducted.

• PNF and Movement
• /
• 제21권2호
• /
• pp.243-253
• /
• 2023

Purpose: This study aimed to investigate the effects of an abdominal drawing-in maneuver (ADIM) with a light load while sitting on transverse abdominis contraction in subjects with and without low back pain. Methods: In this study, 20 participants with chronic low back pain and 20 controls participated. Ultrasonography was used to assess the thickness of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA) muscles. Muscle thickness was measured at rest and during ADIM in three different sitting postures: (1) just sitting, (2) sitting loaded position (holding a 1 or 2 kg dumbbell in each hand), and (3) sitting loaded shoulder flexion position (holding a 1 or 2 kg dumbbell in each hand). Results: The contraction ratio (CR) and preferential activation ratio (PAR) of the TrA during ADIM had no significant interactional effect between the group and the sitting postures. However, the CR and PRA of the TrA during the ADIM showed significant differences among the three different sitting postures. The CR of the TrA during the ADIM in the sitting loaded shoulder flexion position was significantly increased compared to that in the sitting position (p<0.05). Moreover, the PRA of the TrA muscle during ADIM in sitting loaded and sitting loaded shoulder flexion positions was significantly higher than that in the sitting position (p<0.05). Conclusion: The findings suggest that ADIM in the sitting-loaded shoulder flexion position should be implemented to facilitate TrA activity.

• 대한정형도수물리치료학회지
• /
• 제26권1호
• /
• pp.27-36
• /
• 2020

Background: Exercise in the quadruped position is performed to improve body and shoulder stability. This study examined the muscle activity of the trunk muscles according to the distance of the weight shift when lifting one leg in the quadruped position. Methods: Ten healthy 20 to 40 years old males were tested as subjects. All subjects moved their body weight to 0, 5, and 10cm on the opposite side of the leg lifter while maintaining the quadruped position. The surface electrodes recorded the electromyography data during the one leg lifting. Results: As the weight shift distance was increased, there was a significant difference in muscle activity of both serratus anterior, multifidus and internal oblique muscles (p<.05). Left and right serratus anterior and right internal oblique were most activated when weight shift distance was 0cm (p<.05). Conclusion: Shoulder and lumbar stabilization exercises should be applied in the absence of a weight shift distance during quadruped exercise.

• 대한물리의학회지
• /
• 제12권1호
• /
• pp.61-66
• /
• 2017

PURPOSE: The purpose of this study was to investigate the effects of isometric upper limb contraction on the trunk and lower extremity muscles during the sit-to-stand activity in elderly females. METHODS: Eighteen healthy elderly females performed three directional isometric upper extremity contractions (flexion, extension, and horizontal abduction movements) using an elastic band during sit-to-stand activity. Electromyography signals were collected from the internal oblique, erector spinae, rectus femoris, and biceps femoris muscles. RESULTS: Internal oblique activity was greater in bilateral shoulder flexion and bilateral shoulder horizontal abduction than in neutral position (p<.05). Erector spinae and rectus femoris muscle activities in bilateral shoulder flexion was greater than in neutral position and bilateral shoulder extension (p<.05). Biceps femoris activity was significantly greater in bilateral shoulder flexion than in bilateral shoulder extension and horizontal abduction, and in neutral position compared to bilateral shoulder extension (p<.05). CONCLUSION: These results suggest that incorporating isometric upper limb contraction may be beneficial for enhancing the contribution of trunk and lower extremity muscle activities to trunk stabilization during sit-to-stand activity. Therefore, isometric upper limb contraction during sit-to-stand tasks, especially in flexion, may be used to elicit contraction of the lumbopelvic region muscles within a tolerable range, for developing endurance and strength in the elderly.

• The Journal of Korean Physical Therapy
• /
• 제22권6호
• /
• pp.7-12
• /
• 2010

Purpose: This study investigated changes in the thickness of the transversus abdominis (TrA), internal abdominal oblique (IO), and external abdominal oblique (EO) muscles between crook lying and wall support standing positions during abdominal hollowing (AH), using ultrasound imaging. Methods: Experiments were conducted on 20 healthy male adults (mean age=$22.45{\pm}4.08$ years) who voluntarily agreed to participate in the experiments. The changes in the thickness of the subjects' abdominal muscles were measured during AH in crook lying and wall support standing positions. Results: The difference in the thickness of TrA between the two positions during AH was statistically significant, but the differences in the thicknesses of IO and EO were not significant. Conclusion: Activity of the TrA, which is a deep muscle, was stimulated in the standing position, which is, therefore, more functional than the crook position, but the activities of IO and EO muscles did not decrease. Therefore, various methods to induce the activity of TrA while decreasing the activities of IO and EO, in the functional standing position that can stimulate deep muscles, need to be designed.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2008년도 제31회 추계학술대회논문집
• /
• pp.269-272
• /
• 2008

고체 추진기관의 추력을 조절하기 위하여 사용되는 핀틀은 초음속 유동장 내부에 위치하기 때문에 핀틀 팁의 형상과 노즐의 Contour형상에 따라 초음속 노즐 내부는 복잡한 유동장 패턴을 가지게 된다. 본 연구는 핀틀 노즐성능에 대한 연구로 Needle형 핀틀을 사용하여 수행한 공압 시험과 수치해석을 이용하여 핀틀의 위치에 따른 초음속 노즐 내부 유동장 변화가 핀틀 노즐의 추력성능에 미치는 영향에 대하여 분석하였다. 연구의 결과, 노즐 내부에 3가지 충격파가 존재하고 경사충격파의 위치가 핀틀의 위치에 따라 진동함을 알 수 있었다.

• 한국전문물리치료학회지
• /
• 제29권1호
• /
• pp.79-86
• /
• 2022

Background: Bird dog exercise (BDE) is one of the lumbar stabilization exercises that rehabilitate low back pain by co-contraction of the local and global muscles. Previous studies have reported the effect of various type of BDEs (for example, practicing the exercises on various surfaces and changing the limb movement) for muscle co-contraction. Objects: This study aimed to investigate the effect of knee joint flexion position of the raised lower limb on abdominal and back muscle activity during BDE in patients with chronic low back pain (CLBP). Methods: Thirteen males participated in this study (age: 32.54 ± 4.48 years, height: 177.38 ± 7.17 cm). Surface electromyographic (SEMG) data of the internal abdominal oblique (IO), external abdominal oblique (EO), lumbar multifidus (MF), and thoracic part of the iliocostalis lumborum (ICLT) were collected in two knee joint flexion positions (90° flexion versus 0° flexion) during BDE. The SEMG data were expressed as a percentage of root mean square mean values obtained in the maximal voluntary isometric contraction. Results: Greater muscle activity of the IO (p = 0.001), MF (p = 0.009), and ICLT (p = 0.021) of the raised lower limb side and the EO (p = 0.001) and MF (p = 0.009) of the contralateral side were demonstrated in the knee joint flexion position compared to the knee joint extension position. Greater local/global activity ratios of the abdominal muscle (i.e., IO and EO) of the raised lower limb (p = 0.002) and the back muscle (i.e., MF and ICLT) of the contralateral side (p = 0.028) were also noted in the knee joint flexion position. Conclusion: BDE with a knee joint flexion position might be recommended as an alternative lumbar stabilization exercise to enhance muscle activity in both the raised lower limb and the contralateral sides of the trunk for individuals with CLBP.

• 대한치과기공학회지
• /
• 제38권3호
• /
• pp.143-149
• /
• 2016

Purpose: The purpose of this study is to evaluate the effect of two different oblique mechanical loading to occlusal surfaces of cement retained implant on the stress distributions in surrounding bone, using 3-dimensional finite element method. Methods: A 3-dimensional finite element model of a cement retained implant composed of three unit implants, simplified ceramic crown and supporting bone was developed according to the design of ement retained implant for this study. two kinds of surface distributed oblique loads(100 N) are applied to following occlusal surfaces in the single crowns; 1) oblique load on 2 occlusal points(50N for each buccal cusp, 2 buccal cusps exist), 2) oblique load on 4 occlusal points(25N for each buccal and lingual cusp, 2 buccal and 2 lingual cusps exist) Results: The results of the comparison of the stress distributions on surrounding bone are as follows. In the condition of oblique load on 2 occlusal points, VMS was 741.3 Mpa in the M1(Ø$4.0{\times}13mm$) model and 251.2 Mpa in the M2(Ø$5.0{\times}13mm$) model. It means the stress on the supporting bone is decreased. The results of oblique load on 4 occlusal points are similar to this one. Conclusion: Increasing the diameter of the implant fixture is helpful to distribute the stress on the supporting bone. Also, to obtain the structural stability of the supporting bone, it is effective to distribute the load evenly on the occlusal surface of crown in producing single crown implant.

• 대한통합의학회지
• /
• 제9권4호
• /
• pp.283-289
• /
• 2021

Purpose : The purpose of this study is to investigate the effect of mid frequency electrical stimulation during squat exercise on the muscle activity and muscle activity ratio of vastus medialis oblique and vastus lateralis, and to prepare scientific basic data for exercise intervention using mid frequency electrical stimulation. Methods : This study was conducted with students from University C located in Busan, and among a total of 123 subjects, 12 subjects who complained of knee joint dysfunction between 80 and 90 points using the Kujala patellofemoral score (KPS) were used. All subjects participated in the experiment for 3 days, and MVIC values were measured for normalization of muscle activity values on the first day. For the two days, participants participated in the experiment and performed squat exercise or squat exercise receiving mid-frequency electrical stimulation in random order. Measurements were taken in the squat position immediately after the squat exercise, and muscle activities of vastus medialis oblique and vastus lateralis were measured. The measured data were compared through the dependent t test, and the statistical significance level was set to .05. Results : According to the results of this study, in the case of applying mid-frequency electrical stimulation together in the ratio of vastus medialis oblique and vastus lateralis muscle activity during squat exercise, higher values were observed compared to the case of not applying mid-frequency electrical stimulation together, and statistically significant. Also, when mid-frequency electrical stimulation was applied to both vastus medialis oblique and vastus lateralis activities during the squat exercise, higher values were shown compared to the case where the mid-frequency electrical stimulation was not applied together, but there was no statistically significant difference. Conclusion : The results of this study reported that mid-frequency electrical stimulation provided to vastus medialis oblique increased the muscle activity ratio of vastus medialis oblique and vastus lateralis. Therefore, the improvement of coordination due to the enhancement of the activity of vastus medialis oblique through mid-frequency electrical stimulation will be more helpful in the treatment of patellofemoral pain syndrome patient. In addition, it is hoped that the electrical stimulation method applied to exercise will be widely used.