• 한국전문물리치료학회지
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• 제29권1호
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• pp.79-86
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• 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.

• 한국체육학회지인문사회과학편
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• 제54권1호
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• pp.515-525
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• 2015

이 연구는 태권도학과 시범단 8명과 일반학생 8명을 대상자로 선정을 하여 태권도 발차기 동작 시 숙련도에 따른 체간과 하지근육의 근 활성도 비교를 목적으로 실시되었다. 태권도 앞차기, 돌개차기, 뒤후려차기 동작 시 이용되는 주요근육을 표면근전도를 이용하여, 무릎을 들어올리는 동작(P1)과 발을 차는 동작(P2)구간별로 근 활성도를 비교분석하여 다음과 같은 결론을 얻었다. 앞차기 동작 시에는 비숙련자들은 체간의 하부복직근의 활성도와 차는발의 대퇴이두근 및 지지발의 내측광근 및 외측비복근의 활성도가 숙련자보다 높고, 허리세움근 2개의 근활성도는 낮은 것으로 나타났다. 돌개차기(턴차기) 동작 시 회전동작에서는 숙련자들의 대퇴이두근과 척추근의 활성도가 비숙련자보다 높고, 차는동작에서는 하지 근 활성도는 대퇴이두근의 활성도가 높게 나타났다. 뒤후려차기 동작 시 비숙련자들의 차는발 외측비복근과 지지발의 대퇴근육 3개의 근 활성도가 숙련자보다 높게 나타났다. 이상의 결과를 종합해 보면, 숙련자들은 회전동작에서 체간을 사용하며 빠르게 회전하고 차는 발의 근 활성도가 높지 않지만, 비숙련자들은 차는발과 지지발에 근 활성도가 높게 나타났으며, 이는 차는 동작에서 균형을 유지하기 위하여 체간근육보다는 하지에 힘이 들어가 비효율적인 동작을 하는 것으로 나타났다.

• International Journal of Internet, Broadcasting and Communication
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• 제13권1호
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• pp.143-151
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• 2021

The purpose of our study is to confirm the trend of the muscle activity of the trunk and lower limb muscles by the attack method and phase during volleyball exercise. To achieve this purpose, spike serve and spike were conducted for 9 male middle school students, and at that time, it was divided into four phase, such as run jump, take off, impact, and follow, and the rectus abdominis, erector spine, and left rectus femoris, left biceps femoris, left anterior tibialis, left gastrocnemius midialis, right rectus femoris, right biceps femoris, right anterior tibialis, right gastrocnemius midialis, were examined. Spike serve and spike were each performed three times, and randomly cross-allocated to extract accurate data. We was no difference in all muscles according to the attack method, and the muscle activity of the rectus abdominis was highest in the impact phase and the muscle activity of the vertebral spine muscle was highest in the close-up phase. In addition, all of the measured left and right lower limb muscles showed the highest muscle activity between the assisted devices. As a result, We found out that regardless of the method of spike serve and spike, the lower limbs in the run-up phase for a high jump, the vertebrae in the take off phase, the preparation phase for hitting the ball strongly, and in the impact phase at the moment of hitting the ball. It can be seen that it exerts the greatest power in the rectus abdominis.

• 한국운동역학회지
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• 제28권2호
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• pp.93-100
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• 2018

Objective: The purpose of this study is to analyze the kinematic characteristics of the national speed skaters in the curve phase of 500-m race. Method: Seven national skaters participated in the study. Race images were acquired using a high - speed camera, and the three-dimensional motion was analyzed. Results: For skaters, whose average velocity in the curve phase is high, the velocity of entry into the straight phase was also fast. The fast skaters showed a larger maximum angle of extension of the knee joints than the relatively slow skaters, and the trunk ROM was smaller. Fast skaters tended to match the timing of the movement of the lower limb with the pelvis, while slow skaters tended to rotate the left pelvis backward. The velocity of the curve phase did not show a clear relationship with stroke time, average trunk angle, and lap time. Conclusion: It is important to skate close to the inner line, keep the trunk ROM below 10 degrees, extend the knee angle to over 160 degrees, and match the movement of the pelvis and lower limb to accelerate in the curve phase. The average velocity of the curves was fast for many athletes, but the competition rankings were low. Therefore, it is possible to improve the performance by optimizing the start technique, the running characteristics of the straight phase, and the physical factors.

• 한국정밀공학회지
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• 제24권11호
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• pp.116-125
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• 2007

Human muscle skeletal model was developed for biomechanical study. The human model was consists with 19 bone-skeleton and 122 muscles. Muscle number of upper limb, trunk and lower limb part are 28, 60, 34 respectively. Bone was modeled with 3D beam element and muscle was modeled with spar element. For upper limb muscle modelling, rectus abdominis, trapezius, deltoideus, biceps brachii, triceps brachii muscle and other main muscles were considered. Lower limb muscle was modeled with gastrocenemius, gluteus maximus, gluteus medius and related muscles. The biomechanical stress and strain analysis of human was conducted by proposed finite element analysis model under Kumdo head hitting motion. In this study structural analysis has been performed in order to investigate the human body impact by Kumdo head hitting motion. As the results, the analytical displacement, stress and strain of human body are presented.

• International Journal of Safety
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• 제10권1호
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• pp.32-35
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• 2011

Lifting capacity and difficulty of task are influenced by body posture. In RULA and REBA, the body was divided into segments which formed two groups, A and B. Group A includes the upper and lower arm and wrist while group B includes the neck, trunk and legs. This ensures that whole body posture is recorded so that any awkward or constrained posture of the legs, trunk or neck which might influence the posture of the upper limb. This study aimed to measure MVC (maximum voluntary contraction) and subjective judgment in psychophysical method (Borg's scale) according to trunk and upper arm angle and to analyze results statistically. The results of this study were that lifting capacity was more influenced by interaction of body posture rather than angles of each part, and MVC variation according to trunk and upper arms angles should different patterns. This means that we consider the interaction of trunk angles and upper arm angles when we access risk factors of the postures. This survey would be also the basic data to evaluate difficulty of lifting tasks according to body postures ergonomically.

• 대한통합의학회지
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• 제9권2호
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• pp.165-172
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• 2021

Purpose : This study was conducted to find out the effect on the activity of trunk and lower limbs muscles during abdominal drawing-in bridging exercises by verbal cue on the unstable supporting surface after pelvic rearward sloping taping for trunk stabilization movement. Methods : The study subjects were recruited by using the on-campus bulletin boards for healthy adult males and females in their 20s attending K University in Changwon-city, South Gyeongsang Province. The subjects were 30 persons (15 males and 15 females) who agreed to the study purpose in accordance with the criteria for selection and exclusion. Results : The results were obtained by measuring the muscle activity of the trunk and lower limbs during abdominal drawing-in bridging exercises by verbal cue on the unstable supporting surface after pelvic fixed tapping. The effects on erector spinae and hamstring muscles was statistically significantly lower (p<.05), it was confirmed that there were no statistically significant differences between the multifidus and gluteus maximus muscle (p>.05). Conclusion : Through this study, it was found that the excessive flexion of the waist was significantly reduced from erector spinalis and hamstring muscle after abdominal drawing-in bridging exercises by verbal cue on the unstable supporting surface after pelvic rearward sloping tapping compared to the general bridging exercises.

• 한국정밀공학회지
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• 제25권9호
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• pp.126-134
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• 2008

Kendo is one of the popular sports in modem life. Head, wrist and thrust attack are the fast skill to get a score on a match. Human muscle skeletal model was developed for biomechanical study. The human model was consists with 19 bone-skeleton and 122 muscles. Muscle number of upper limb, trunk and lower limb part are 28, 60, 34 respectively. Bone was modeled with 3D beam element and muscle was modeled with spar element. For upper limb muscle modelling, rectus abdominis, trapezius, deltoideus, biceps brachii, triceps brachii muscle and other main muscles were considered. Lower limb muscle was modeled with gastrocenemius, gluteus maximus, gluteus medius and related muscles. The biomechanical stress and strain analysis of human muscle was conducted by proposed human bone-muscle finite element analysis model under head, wrist and thrust attack for kendo training.

• 대한물리의학회지
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• 제12권3호
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• pp.85-91
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• 2017

PURPOSE: The purpose of this study was to compare muscle activation of the trunk and lower limbs of subjects wearing high-heeled or flat shoes while crossing over obstacles of different heights. METHODS: Twenty subjects participated in this study. While wearing high-heeled shoes (7 cm) or flat shoes (0 cm), the subjects were asked to cross over obstacles of different heights (10%, 20%, and 30% of their lower-limb length). Muscle activation of the trunk and lower limbs with the supported side while crossing over obstacles of different heights was measured using the electromyogram (Noraxon, DTS, Germany). Two-way repeated ANOVA was used to compare the muscle activation between high-heel shoes and flat shoes while crossing over obstacles of different heights. All statistical analyses were performed using SPSS ver. 21, and p-values less than .05 were used to identify significant differences. RESULTS: As an obstacle's height increased, muscle activation of the trunk and lower limbs with the supported side was increased while wearing either type of shoe, and it was generally higher while wearing high-heeled shoes. However, tibialis anterior muscle activity while wearing high-heeled shoes was lower than while wearing flat shoes. CONCLUSION: This study showed that muscle activation of the trunk and lower limbs was higher when subjects wore high-heeled shoes than when they wore flat shoes while crossing over obstacles of different heights. Therefore, high-heeled shoes can easily cause high muscle fatigue of the trunk and lower limbs, and the TA muscle may weaken in persons who wear high-heeled shoes.

• 한국운동역학회지
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• 제17권1호
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• pp.111-119
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• 2007

The purpose of this study was to investigate muscle activity and gait pattern in lower limb depending on the outsole of heel rockers. Fifteen healthy men volunteered for this experiment. Each subject performed totally three trails with two pairs of different heel rocker shoes and a pair of normal running shoes at speed of 1.33m/s for 1 minute during walking on a treadmill. Kinematic data gathered in 100Hz was recorded and analyzed by using the 3D motion capture system to measure the trunk tilt and joint angle of the right lower limb. And the lower extremity muscle activities were simultaneously recorded in 1000Hz and assessed by using EMG. The statistical analysis was the one-way ANOVA with the repeated measures to compare among the three kinds of shoes. The level of statistical significance for all tests was 0.05. Joint angle of lower limb was showed statistically significant different in MST(hip joint), LHS(ankle joint), and RTO(knee and ankle joint). Muscle activity of rectus femoris and biceps femoris was statistically increased in both heel rocker shoes during gait cycle on treadmill. The maximum peak time of tibialis anterior in the negative heel rocker showed the delay of approximately 23.8%time than normal shoes. Gait pattern variability of the negative heel rocker was increased in the first half of the stance phase and the variability of the positive heel rocker was increased in the terminal stance phase. In Conclusion, stability was decreased in between joints of lower limb on positive heel rocker than negative heel rocker. This study found that there were different joint angle, muscle activity, gait pattern and coordinate system of the lower limb in each kind of shoes. These unstability affected the lower extremity and the whole body. A further study has to be continued with study of rehabilitation and exercise for a long-term.